Merge pull request #1631 from QuLogic/split-dependencies

Split dependencies.py into separate files

7 files changed, 1966 insertions, 1815 deletions

diff --git a/mesonbuild/dependencies.py b/mesonbuild/dependencies.py
deleted file mode 100644
index d9a7c9c..0000000
--- a/mesonbuild/dependencies.py
+++ /dev/null
@@ -1,1815 +0,0 @@
-# Copyright 2013-2017 The Meson development team
-
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-
-#     http://www.apache.org/licenses/LICENSE-2.0
-
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# This file contains the detection logic for external
-# dependencies. Mostly just uses pkg-config but also contains
-# custom logic for packages that don't provide them.
-
-# Currently one file, should probably be split into a
-# package before this gets too big.
-
-import re
-import sys
-import os, stat, glob, shutil
-import shlex
-import subprocess
-import sysconfig
-from enum import Enum
-from collections import OrderedDict
-from . import mlog
-from . import mesonlib
-from .mesonlib import Popen_safe, flatten
-from .mesonlib import MesonException, version_compare, version_compare_many
-from .environment import detect_cpu_family, for_windows
-
-class DependencyException(MesonException):
-    '''Exceptions raised while trying to find dependencies'''
-
-class DependencyMethods(Enum):
-    # Auto means to use whatever dependency checking mechanisms in whatever order meson thinks is best.
-    AUTO = 'auto'
-    PKGCONFIG = 'pkg-config'
-    QMAKE = 'qmake'
-    # Just specify the standard link arguments, assuming the operating system provides the library.
-    SYSTEM = 'system'
-    # Detect using sdl2-config
-    SDLCONFIG = 'sdlconfig'
-    # This is only supported on OSX - search the frameworks directory by name.
-    EXTRAFRAMEWORK = 'extraframework'
-    # Detect using the sysconfig module.
-    SYSCONFIG = 'sysconfig'
-
-class Dependency:
-    def __init__(self, type_name, kwargs):
-        self.name = "null"
-        self.language = None
-        self.is_found = False
-        self.type_name = type_name
-        method = DependencyMethods(kwargs.get('method', 'auto'))
-
-        # Set the detection method. If the method is set to auto, use any available method.
-        # If method is set to a specific string, allow only that detection method.
-        if method == DependencyMethods.AUTO:
-            self.methods = self.get_methods()
-        elif method in self.get_methods():
-            self.methods = [method]
-        else:
-            raise MesonException('Unsupported detection method: {}, allowed methods are {}'.format(method.value, mlog.format_list(map(lambda x: x.value, [DependencyMethods.AUTO] + self.get_methods()))))
-
-    def __repr__(self):
-        s = '<{0} {1}: {2}>'
-        return s.format(self.__class__.__name__, self.name, self.is_found)
-
-    def get_compile_args(self):
-        return []
-
-    def get_link_args(self):
-        return []
-
-    def found(self):
-        return self.is_found
-
-    def get_sources(self):
-        """Source files that need to be added to the target.
-        As an example, gtest-all.cc when using GTest."""
-        return []
-
-    def get_methods(self):
-        return [DependencyMethods.AUTO]
-
-    def get_name(self):
-        return self.name
-
-    def get_exe_args(self, compiler):
-        return []
-
-    def need_threads(self):
-        return False
-
-    def get_pkgconfig_variable(self, variable_name):
-        raise MesonException('Tried to get a pkg-config variable from a non-pkgconfig dependency.')
-
-class InternalDependency(Dependency):
-    def __init__(self, version, incdirs, compile_args, link_args, libraries, sources, ext_deps):
-        super().__init__('internal', {})
-        self.version = version
-        self.is_found = True
-        self.include_directories = incdirs
-        self.compile_args = compile_args
-        self.link_args = link_args
-        self.libraries = libraries
-        self.sources = sources
-        self.ext_deps = ext_deps
-
-    def get_compile_args(self):
-        return self.compile_args
-
-    def get_link_args(self):
-        return self.link_args
-
-    def get_version(self):
-        return self.version
-
-class PkgConfigDependency(Dependency):
-    # The class's copy of the pkg-config path. Avoids having to search for it
-    # multiple times in the same Meson invocation.
-    class_pkgbin = None
-
-    def __init__(self, name, environment, kwargs):
-        Dependency.__init__(self, 'pkgconfig', kwargs)
-        self.is_libtool = False
-        self.version_reqs = kwargs.get('version', None)
-        self.required = kwargs.get('required', True)
-        self.static = kwargs.get('static', False)
-        self.silent = kwargs.get('silent', False)
-        if not isinstance(self.static, bool):
-            raise DependencyException('Static keyword must be boolean')
-        # Store a copy of the pkg-config path on the object itself so it is
-        # stored in the pickled coredata and recovered.
-        self.pkgbin = None
-        self.cargs = []
-        self.libs = []
-        if 'native' in kwargs and environment.is_cross_build():
-            self.want_cross = not kwargs['native']
-        else:
-            self.want_cross = environment.is_cross_build()
-        self.name = name
-        self.modversion = 'none'
-
-        # When finding dependencies for cross-compiling, we don't care about
-        # the 'native' pkg-config
-        if self.want_cross:
-            if 'pkgconfig' not in environment.cross_info.config['binaries']:
-                if self.required:
-                    raise DependencyException('Pkg-config binary missing from cross file')
-            else:
-                pkgname = environment.cross_info.config['binaries']['pkgconfig']
-                potential_pkgbin = ExternalProgram(pkgname, silent=True)
-                if potential_pkgbin.found():
-                    # FIXME, we should store all pkg-configs in ExternalPrograms.
-                    # However that is too destabilizing a change to do just before release.
-                    self.pkgbin = potential_pkgbin.get_command()[0]
-                    PkgConfigDependency.class_pkgbin = self.pkgbin
-                else:
-                    mlog.debug('Cross pkg-config %s not found.' % potential_pkgbin.name)
-        # Only search for the native pkg-config the first time and
-        # store the result in the class definition
-        elif PkgConfigDependency.class_pkgbin is None:
-            self.pkgbin = self.check_pkgconfig()
-            PkgConfigDependency.class_pkgbin = self.pkgbin
-        else:
-            self.pkgbin = PkgConfigDependency.class_pkgbin
-
-        self.is_found = False
-        if not self.pkgbin:
-            if self.required:
-                raise DependencyException('Pkg-config not found.')
-            return
-        if self.want_cross:
-            self.type_string = 'Cross'
-        else:
-            self.type_string = 'Native'
-
-        mlog.debug('Determining dependency {!r} with pkg-config executable '
-                   '{!r}'.format(name, self.pkgbin))
-        ret, self.modversion = self._call_pkgbin(['--modversion', name])
-        if ret != 0:
-            if self.required:
-                raise DependencyException('{} dependency {!r} not found'
-                                          ''.format(self.type_string, name))
-            return
-        found_msg = [self.type_string + ' dependency', mlog.bold(name), 'found:']
-        if self.version_reqs is None:
-            self.is_found = True
-        else:
-            if not isinstance(self.version_reqs, (str, list)):
-                raise DependencyException('Version argument must be string or list.')
-            if isinstance(self.version_reqs, str):
-                self.version_reqs = [self.version_reqs]
-            (self.is_found, not_found, found) = \
-                version_compare_many(self.modversion, self.version_reqs)
-            if not self.is_found:
-                found_msg += [mlog.red('NO'),
-                              'found {!r} but need:'.format(self.modversion),
-                              ', '.join(["'{}'".format(e) for e in not_found])]
-                if found:
-                    found_msg += ['; matched:',
-                                  ', '.join(["'{}'".format(e) for e in found])]
-                if not self.silent:
-                    mlog.log(*found_msg)
-                if self.required:
-                    m = 'Invalid version of dependency, need {!r} {!r} found {!r}.'
-                    raise DependencyException(m.format(name, not_found, self.modversion))
-                return
-        found_msg += [mlog.green('YES'), self.modversion]
-        # Fetch cargs to be used while using this dependency
-        self._set_cargs()
-        # Fetch the libraries and library paths needed for using this
-        self._set_libs()
-        # Print the found message only at the very end because fetching cflags
-        # and libs can also fail if other needed pkg-config files aren't found.
-        if not self.silent:
-            mlog.log(*found_msg)
-
-    def __repr__(self):
-        s = '<{0} {1}: {2} {3}>'
-        return s.format(self.__class__.__name__, self.name, self.is_found,
-                        self.version_reqs)
-
-    def _call_pkgbin(self, args):
-        p, out = Popen_safe([self.pkgbin] + args, env=os.environ)[0:2]
-        return p.returncode, out.strip()
-
-    def _set_cargs(self):
-        ret, out = self._call_pkgbin(['--cflags', self.name])
-        if ret != 0:
-            raise DependencyException('Could not generate cargs for %s:\n\n%s' %
-                                      (self.name, out))
-        self.cargs = out.split()
-
-    def _set_libs(self):
-        libcmd = [self.name, '--libs']
-        if self.static:
-            libcmd.append('--static')
-        ret, out = self._call_pkgbin(libcmd)
-        if ret != 0:
-            raise DependencyException('Could not generate libs for %s:\n\n%s' %
-                                      (self.name, out))
-        self.libs = []
-        for lib in out.split():
-            if lib.endswith(".la"):
-                shared_libname = self.extract_libtool_shlib(lib)
-                shared_lib = os.path.join(os.path.dirname(lib), shared_libname)
-                if not os.path.exists(shared_lib):
-                    shared_lib = os.path.join(os.path.dirname(lib), ".libs", shared_libname)
-
-                if not os.path.exists(shared_lib):
-                    raise DependencyException('Got a libtools specific "%s" dependencies'
-                                              'but we could not compute the actual shared'
-                                              'library path' % lib)
-                lib = shared_lib
-                self.is_libtool = True
-            self.libs.append(lib)
-
-    def get_pkgconfig_variable(self, variable_name):
-        ret, out = self._call_pkgbin(['--variable=' + variable_name, self.name])
-        variable = ''
-        if ret != 0:
-            if self.required:
-                raise DependencyException('%s dependency %s not found.' %
-                                          (self.type_string, self.name))
-        else:
-            variable = out.strip()
-        mlog.debug('Got pkgconfig variable %s : %s' % (variable_name, variable))
-        return variable
-
-    def get_modversion(self):
-        return self.modversion
-
-    def get_version(self):
-        return self.modversion
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
-    def get_methods(self):
-        return [DependencyMethods.PKGCONFIG]
-
-    def check_pkgconfig(self):
-        evar = 'PKG_CONFIG'
-        if evar in os.environ:
-            pkgbin = os.environ[evar].strip()
-        else:
-            pkgbin = 'pkg-config'
-        try:
-            p, out = Popen_safe([pkgbin, '--version'])[0:2]
-            if p.returncode != 0:
-                # Set to False instead of None to signify that we've already
-                # searched for it and not found it
-                pkgbin = False
-        except (FileNotFoundError, PermissionError):
-            pkgbin = False
-        if pkgbin and not os.path.isabs(pkgbin) and shutil.which(pkgbin):
-            # Sometimes shutil.which fails where Popen succeeds, so
-            # only find the abs path if it can be found by shutil.which
-            pkgbin = shutil.which(pkgbin)
-        if not self.silent:
-            if pkgbin:
-                mlog.log('Found pkg-config:', mlog.bold(pkgbin),
-                         '(%s)' % out.strip())
-            else:
-                mlog.log('Found Pkg-config:', mlog.red('NO'))
-        return pkgbin
-
-    def found(self):
-        return self.is_found
-
-    def extract_field(self, la_file, fieldname):
-        with open(la_file) as f:
-            for line in f:
-                arr = line.strip().split('=')
-                if arr[0] == fieldname:
-                    return arr[1][1:-1]
-        return None
-
-    def extract_dlname_field(self, la_file):
-        return self.extract_field(la_file, 'dlname')
-
-    def extract_libdir_field(self, la_file):
-        return self.extract_field(la_file, 'libdir')
-
-    def extract_libtool_shlib(self, la_file):
-        '''
-        Returns the path to the shared library
-        corresponding to this .la file
-        '''
-        dlname = self.extract_dlname_field(la_file)
-        if dlname is None:
-            return None
-
-        # Darwin uses absolute paths where possible; since the libtool files never
-        # contain absolute paths, use the libdir field
-        if mesonlib.is_osx():
-            dlbasename = os.path.basename(dlname)
-            libdir = self.extract_libdir_field(la_file)
-            if libdir is None:
-                return dlbasename
-            return os.path.join(libdir, dlbasename)
-        # From the comments in extract_libtool(), older libtools had
-        # a path rather than the raw dlname
-        return os.path.basename(dlname)
-
-class WxDependency(Dependency):
-    wx_found = None
-
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'wx', kwargs)
-        self.is_found = False
-        # FIXME: use version instead of modversion
-        self.modversion = 'none'
-        if WxDependency.wx_found is None:
-            self.check_wxconfig()
-        if not WxDependency.wx_found:
-            # FIXME: this message could be printed after Dependncy found
-            mlog.log("Neither wx-config-3.0 nor wx-config found; can't detect dependency")
-            return
-
-        # FIXME: This should print stdout and stderr using mlog.debug
-        p, out = Popen_safe([self.wxc, '--version'])[0:2]
-        if p.returncode != 0:
-            mlog.log('Dependency wxwidgets found:', mlog.red('NO'))
-            self.cargs = []
-            self.libs = []
-        else:
-            self.modversion = out.strip()
-            version_req = kwargs.get('version', None)
-            if version_req is not None:
-                if not version_compare(self.modversion, version_req, strict=True):
-                    mlog.log('Wxwidgets version %s does not fullfill requirement %s' %
-                             (self.modversion, version_req))
-                    return
-            mlog.log('Dependency wxwidgets found:', mlog.green('YES'))
-            self.is_found = True
-            self.requested_modules = self.get_requested(kwargs)
-            # wx-config seems to have a cflags as well but since it requires C++,
-            # this should be good, at least for now.
-            p, out = Popen_safe([self.wxc, '--cxxflags'])[0:2]
-            # FIXME: this error should only be raised if required is true
-            if p.returncode != 0:
-                raise DependencyException('Could not generate cargs for wxwidgets.')
-            self.cargs = out.split()
-
-            # FIXME: this error should only be raised if required is true
-            p, out = Popen_safe([self.wxc, '--libs'] + self.requested_modules)[0:2]
-            if p.returncode != 0:
-                raise DependencyException('Could not generate libs for wxwidgets.')
-            self.libs = out.split()
-
-    def get_requested(self, kwargs):
-        modules = 'modules'
-        if modules not in kwargs:
-            return []
-        candidates = kwargs[modules]
-        if isinstance(candidates, str):
-            return [candidates]
-        for c in candidates:
-            if not isinstance(c, str):
-                raise DependencyException('wxwidgets module argument is not a string.')
-        return candidates
-
-    def get_modversion(self):
-        return self.modversion
-
-    def get_version(self):
-        return self.modversion
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
-    def check_wxconfig(self):
-        for wxc in ['wx-config-3.0', 'wx-config']:
-            try:
-                p, out = Popen_safe([wxc, '--version'])[0:2]
-                if p.returncode == 0:
-                    mlog.log('Found wx-config:', mlog.bold(shutil.which(wxc)),
-                             '(%s)' % out.strip())
-                    self.wxc = wxc
-                    WxDependency.wx_found = True
-                    return
-            except (FileNotFoundError, PermissionError):
-                pass
-        WxDependency.wxconfig_found = False
-        mlog.log('Found wx-config:', mlog.red('NO'))
-
-    def found(self):
-        return self.is_found
-
-class ExternalProgram:
-    windows_exts = ('exe', 'msc', 'com', 'bat')
-
-    def __init__(self, name, command=None, silent=False, search_dir=None):
-        self.name = name
-        if command is not None:
-            if not isinstance(command, list):
-                self.command = [command]
-            else:
-                self.command = command
-        else:
-            self.command = self._search(name, search_dir)
-        if not silent:
-            if self.found():
-                mlog.log('Program', mlog.bold(name), 'found:', mlog.green('YES'),
-                         '(%s)' % ' '.join(self.command))
-            else:
-                mlog.log('Program', mlog.bold(name), 'found:', mlog.red('NO'))
-
-    def __repr__(self):
-        r = '<{} {!r} -> {!r}>'
-        return r.format(self.__class__.__name__, self.name, self.command)
-
-    @staticmethod
-    def _shebang_to_cmd(script):
-        """
-        Check if the file has a shebang and manually parse it to figure out
-        the interpreter to use. This is useful if the script is not executable
-        or if we're on Windows (which does not understand shebangs).
-        """
-        try:
-            with open(script) as f:
-                first_line = f.readline().strip()
-            if first_line.startswith('#!'):
-                commands = first_line[2:].split('#')[0].strip().split()
-                if mesonlib.is_windows():
-                    # Windows does not have UNIX paths so remove them,
-                    # but don't remove Windows paths
-                    if commands[0].startswith('/'):
-                        commands[0] = commands[0].split('/')[-1]
-                    if len(commands) > 0 and commands[0] == 'env':
-                        commands = commands[1:]
-                    # Windows does not ship python3.exe, but we know the path to it
-                    if len(commands) > 0 and commands[0] == 'python3':
-                        commands[0] = sys.executable
-                return commands + [script]
-        except Exception:
-            pass
-        return False
-
-    def _is_executable(self, path):
-        suffix = os.path.splitext(path)[-1].lower()[1:]
-        if mesonlib.is_windows():
-            if suffix in self.windows_exts:
-                return True
-        elif os.access(path, os.X_OK):
-            return not os.path.isdir(path)
-        return False
-
-    def _search_dir(self, name, search_dir):
-        if search_dir is None:
-            return False
-        trial = os.path.join(search_dir, name)
-        if os.path.exists(trial):
-            if self._is_executable(trial):
-                return [trial]
-            # Now getting desperate. Maybe it is a script file that is
-            # a) not chmodded executable, or
-            # b) we are on windows so they can't be directly executed.
-            return self._shebang_to_cmd(trial)
-        else:
-            if mesonlib.is_windows():
-                for ext in self.windows_exts:
-                    trial_ext = '{}.{}'.format(trial, ext)
-                    if os.path.exists(trial_ext):
-                        return [trial_ext]
-        return False
-
-    def _search(self, name, search_dir):
-        '''
-        Search in the specified dir for the specified executable by name
-        and if not found search in PATH
-        '''
-        commands = self._search_dir(name, search_dir)
-        if commands:
-            return commands
-        # Do a standard search in PATH
-        command = shutil.which(name)
-        if not mesonlib.is_windows():
-            # On UNIX-like platforms, shutil.which() is enough to find
-            # all executables whether in PATH or with an absolute path
-            return [command]
-        # HERE BEGINS THE TERROR OF WINDOWS
-        if command:
-            # On Windows, even if the PATH search returned a full path, we can't be
-            # sure that it can be run directly if it's not a native executable.
-            # For instance, interpreted scripts sometimes need to be run explicitly
-            # with an interpreter if the file association is not done properly.
-            name_ext = os.path.splitext(command)[1]
-            if name_ext[1:].lower() in self.windows_exts:
-                # Good, it can be directly executed
-                return [command]
-            # Try to extract the interpreter from the shebang
-            commands = self._shebang_to_cmd(command)
-            if commands:
-                return commands
-        else:
-            # Maybe the name is an absolute path to a native Windows
-            # executable, but without the extension. This is technically wrong,
-            # but many people do it because it works in the MinGW shell.
-            if os.path.isabs(name):
-                for ext in self.windows_exts:
-                    command = '{}.{}'.format(name, ext)
-                    if os.path.exists(command):
-                        return [command]
-            # On Windows, interpreted scripts must have an extension otherwise they
-            # cannot be found by a standard PATH search. So we do a custom search
-            # where we manually search for a script with a shebang in PATH.
-            search_dirs = os.environ.get('PATH', '').split(';')
-            for search_dir in search_dirs:
-                commands = self._search_dir(name, search_dir)
-                if commands:
-                    return commands
-        return [None]
-
-    def found(self):
-        return self.command[0] is not None
-
-    def get_command(self):
-        return self.command[:]
-
-    def get_path(self):
-        if self.found():
-            # Assume that the last element is the full path to the script or
-            # binary being run
-            return self.command[-1]
-        return None
-
-    def get_name(self):
-        return self.name
-
-class ExternalLibrary(Dependency):
-    # TODO: Add `language` support to all Dependency objects so that languages
-    # can be exposed for dependencies that support that (i.e., not pkg-config)
-    def __init__(self, name, link_args, language, silent=False):
-        super().__init__('external', {})
-        self.name = name
-        self.language = language
-        self.is_found = False
-        self.link_args = []
-        self.lang_args = []
-        if link_args:
-            self.is_found = True
-            if not isinstance(link_args, list):
-                link_args = [link_args]
-            self.lang_args = {language: link_args}
-            # We special-case Vala for now till the Dependency object gets
-            # proper support for exposing the language it was written in.
-            # Without this, vala-specific link args will end up in the C link
-            # args list if you link to a Vala library.
-            # This hack use to be in CompilerHolder.find_library().
-            if language != 'vala':
-                self.link_args = link_args
-        if not silent:
-            if self.is_found:
-                mlog.log('Library', mlog.bold(name), 'found:', mlog.green('YES'))
-            else:
-                mlog.log('Library', mlog.bold(name), 'found:', mlog.red('NO'))
-
-    def found(self):
-        return self.is_found
-
-    def get_name(self):
-        return self.name
-
-    def get_link_args(self):
-        return self.link_args
-
-    def get_lang_args(self, lang):
-        if lang in self.lang_args:
-            return self.lang_args[lang]
-        return []
-
-class BoostDependency(Dependency):
-    # Some boost libraries have different names for
-    # their sources and libraries. This dict maps
-    # between the two.
-    name2lib = {'test': 'unit_test_framework'}
-
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'boost', kwargs)
-        self.name = 'boost'
-        self.environment = environment
-        self.libdir = ''
-        if 'native' in kwargs and environment.is_cross_build():
-            self.want_cross = not kwargs['native']
-        else:
-            self.want_cross = environment.is_cross_build()
-        try:
-            self.boost_root = os.environ['BOOST_ROOT']
-            if not os.path.isabs(self.boost_root):
-                raise DependencyException('BOOST_ROOT must be an absolute path.')
-        except KeyError:
-            self.boost_root = None
-        if self.boost_root is None:
-            if self.want_cross:
-                if 'BOOST_INCLUDEDIR' in os.environ:
-                    self.incdir = os.environ['BOOST_INCLUDEDIR']
-                else:
-                    raise DependencyException('BOOST_ROOT or BOOST_INCLUDEDIR is needed while cross-compiling')
-            if mesonlib.is_windows():
-                self.boost_root = self.detect_win_root()
-                self.incdir = self.boost_root
-            else:
-                if 'BOOST_INCLUDEDIR' in os.environ:
-                    self.incdir = os.environ['BOOST_INCLUDEDIR']
-                else:
-                    self.incdir = '/usr/include'
-        else:
-            self.incdir = os.path.join(self.boost_root, 'include')
-        self.boost_inc_subdir = os.path.join(self.incdir, 'boost')
-        mlog.debug('Boost library root dir is', self.boost_root)
-        self.src_modules = {}
-        self.lib_modules = {}
-        self.lib_modules_mt = {}
-        self.detect_version()
-        self.requested_modules = self.get_requested(kwargs)
-        module_str = ', '.join(self.requested_modules)
-        if self.version is not None:
-            self.detect_src_modules()
-            self.detect_lib_modules()
-            self.validate_requested()
-            if self.boost_root is not None:
-                info = self.version + ', ' + self.boost_root
-            else:
-                info = self.version
-            mlog.log('Dependency Boost (%s) found:' % module_str, mlog.green('YES'), info)
-        else:
-            mlog.log("Dependency Boost (%s) found:" % module_str, mlog.red('NO'))
-        if 'cpp' not in self.environment.coredata.compilers:
-            raise DependencyException('Tried to use Boost but a C++ compiler is not defined.')
-        self.cpp_compiler = self.environment.coredata.compilers['cpp']
-
-    def detect_win_root(self):
-        globtext = 'c:\\local\\boost_*'
-        files = glob.glob(globtext)
-        if len(files) > 0:
-            return files[0]
-        return 'C:\\'
-
-    def get_compile_args(self):
-        args = []
-        include_dir = ''
-        if self.boost_root is not None:
-            if mesonlib.is_windows():
-                include_dir = self.boost_root
-            else:
-                include_dir = os.path.join(self.boost_root, 'include')
-        else:
-            include_dir = self.incdir
-
-        # Use "-isystem" when including boost headers instead of "-I"
-        # to avoid compiler warnings/failures when "-Werror" is used
-
-        # Careful not to use "-isystem" on default include dirs as it
-        # breaks some of the headers for certain gcc versions
-
-        # For example, doing g++ -isystem /usr/include on a simple
-        # "int main()" source results in the error:
-        # "/usr/include/c++/6.3.1/cstdlib:75:25: fatal error: stdlib.h: No such file or directory"
-
-        # See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129
-        # and http://stackoverflow.com/questions/37218953/isystem-on-a-system-include-directory-causes-errors
-        # for more details
-
-        # TODO: The correct solution would probably be to ask the
-        # compiler for it's default include paths (ie: "gcc -xc++ -E
-        # -v -") and avoid including those with -isystem
-
-        # For now, use -isystem for all includes except for some
-        # typical defaults (which don't need to be included at all
-        # since they are in the default include paths)
-        if include_dir != '/usr/include' and include_dir != '/usr/local/include':
-            args.append("".join(self.cpp_compiler.get_include_args(include_dir, True)))
-        return args
-
-    def get_requested(self, kwargs):
-        candidates = kwargs.get('modules', [])
-        if isinstance(candidates, str):
-            return [candidates]
-        for c in candidates:
-            if not isinstance(c, str):
-                raise DependencyException('Boost module argument is not a string.')
-        return candidates
-
-    def validate_requested(self):
-        for m in self.requested_modules:
-            if m not in self.src_modules:
-                raise DependencyException('Requested Boost module "%s" not found.' % m)
-
-    def found(self):
-        return self.version is not None
-
-    def get_version(self):
-        return self.version
-
-    def detect_version(self):
-        try:
-            ifile = open(os.path.join(self.boost_inc_subdir, 'version.hpp'))
-        except FileNotFoundError:
-            self.version = None
-            return
-        with ifile:
-            for line in ifile:
-                if line.startswith("#define") and 'BOOST_LIB_VERSION' in line:
-                    ver = line.split()[-1]
-                    ver = ver[1:-1]
-                    self.version = ver.replace('_', '.')
-                    return
-        self.version = None
-
-    def detect_src_modules(self):
-        for entry in os.listdir(self.boost_inc_subdir):
-            entry = os.path.join(self.boost_inc_subdir, entry)
-            if stat.S_ISDIR(os.stat(entry).st_mode):
-                self.src_modules[os.path.split(entry)[-1]] = True
-
-    def detect_lib_modules(self):
-        if mesonlib.is_windows():
-            return self.detect_lib_modules_win()
-        return self.detect_lib_modules_nix()
-
-    def detect_lib_modules_win(self):
-        arch = detect_cpu_family(self.environment.coredata.compilers)
-        # Guess the libdir
-        if arch == 'x86':
-            gl = 'lib32*'
-        elif arch == 'x86_64':
-            gl = 'lib64*'
-        else:
-            # Does anyone do Boost cross-compiling to other archs on Windows?
-            gl = None
-        # See if the libdir is valid
-        if gl:
-            libdir = glob.glob(os.path.join(self.boost_root, gl))
-        else:
-            libdir = []
-        # Can't find libdir, bail
-        if not libdir:
-            return
-        libdir = libdir[0]
-        self.libdir = libdir
-        globber = 'boost_*-gd-*.lib' # FIXME
-        for entry in glob.glob(os.path.join(libdir, globber)):
-            (_, fname) = os.path.split(entry)
-            base = fname.split('_', 1)[1]
-            modname = base.split('-', 1)[0]
-            self.lib_modules_mt[modname] = fname
-
-    def detect_lib_modules_nix(self):
-        if mesonlib.is_osx():
-            libsuffix = 'dylib'
-        else:
-            libsuffix = 'so'
-
-        globber = 'libboost_*.{}'.format(libsuffix)
-        if 'BOOST_LIBRARYDIR' in os.environ:
-            libdirs = [os.environ['BOOST_LIBRARYDIR']]
-        elif self.boost_root is None:
-            libdirs = mesonlib.get_library_dirs()
-        else:
-            libdirs = [os.path.join(self.boost_root, 'lib')]
-        for libdir in libdirs:
-            for entry in glob.glob(os.path.join(libdir, globber)):
-                lib = os.path.basename(entry)
-                name = lib.split('.')[0].split('_', 1)[-1]
-                # I'm not 100% sure what to do here. Some distros
-                # have modules such as thread only as -mt versions.
-                if entry.endswith('-mt.so'):
-                    self.lib_modules_mt[name] = True
-                else:
-                    self.lib_modules[name] = True
-
-    def get_win_link_args(self):
-        args = []
-        if self.boost_root:
-            args.append('-L' + self.libdir)
-        for module in self.requested_modules:
-            module = BoostDependency.name2lib.get(module, module)
-            if module in self.lib_modules_mt:
-                args.append(self.lib_modules_mt[module])
-        return args
-
-    def get_link_args(self):
-        if mesonlib.is_windows():
-            return self.get_win_link_args()
-        args = []
-        if self.boost_root:
-            args.append('-L' + os.path.join(self.boost_root, 'lib'))
-        elif 'BOOST_LIBRARYDIR' in os.environ:
-            args.append('-L' + os.environ['BOOST_LIBRARYDIR'])
-        for module in self.requested_modules:
-            module = BoostDependency.name2lib.get(module, module)
-            libname = 'boost_' + module
-            # The compiler's library detector is the most reliable so use that first.
-            default_detect = self.cpp_compiler.find_library(libname, self.environment, [])
-            if default_detect is not None:
-                if module == 'unit_testing_framework':
-                    emon_args = self.cpp_compiler.find_library('boost_test_exec_monitor')
-                else:
-                    emon_args = None
-                args += default_detect
-                if emon_args is not None:
-                    args += emon_args
-            elif module in self.lib_modules or module in self.lib_modules_mt:
-                linkcmd = '-l' + libname
-                args.append(linkcmd)
-                # FIXME a hack, but Boost's testing framework has a lot of
-                # different options and it's hard to determine what to do
-                # without feedback from actual users. Update this
-                # as we get more bug reports.
-                if module == 'unit_testing_framework':
-                    args.append('-lboost_test_exec_monitor')
-            elif module + '-mt' in self.lib_modules_mt:
-                linkcmd = '-lboost_' + module + '-mt'
-                args.append(linkcmd)
-                if module == 'unit_testing_framework':
-                    args.append('-lboost_test_exec_monitor-mt')
-        return args
-
-    def get_sources(self):
-        return []
-
-    def need_threads(self):
-        return 'thread' in self.requested_modules
-
-class GTestDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gtest', kwargs)
-        self.main = kwargs.get('main', False)
-        self.name = 'gtest'
-        self.libname = 'libgtest.so'
-        self.libmain_name = 'libgtest_main.so'
-        self.include_dir = '/usr/include'
-        self.src_dirs = ['/usr/src/gtest/src', '/usr/src/googletest/googletest/src']
-        self.detect()
-
-    def found(self):
-        return self.is_found
-
-    def detect(self):
-        trial_dirs = mesonlib.get_library_dirs()
-        glib_found = False
-        gmain_found = False
-        for d in trial_dirs:
-            if os.path.isfile(os.path.join(d, self.libname)):
-                glib_found = True
-            if os.path.isfile(os.path.join(d, self.libmain_name)):
-                gmain_found = True
-        if glib_found and gmain_found:
-            self.is_found = True
-            self.compile_args = []
-            self.link_args = ['-lgtest']
-            if self.main:
-                self.link_args.append('-lgtest_main')
-            self.sources = []
-            mlog.log('Dependency GTest found:', mlog.green('YES'), '(prebuilt)')
-        elif self.detect_srcdir():
-            self.is_found = True
-            self.compile_args = ['-I' + self.src_include_dir]
-            self.link_args = []
-            if self.main:
-                self.sources = [self.all_src, self.main_src]
-            else:
-                self.sources = [self.all_src]
-            mlog.log('Dependency GTest found:', mlog.green('YES'), '(building self)')
-        else:
-            mlog.log('Dependency GTest found:', mlog.red('NO'))
-            self.is_found = False
-        return self.is_found
-
-    def detect_srcdir(self):
-        for s in self.src_dirs:
-            if os.path.exists(s):
-                self.src_dir = s
-                self.all_src = mesonlib.File.from_absolute_file(
-                    os.path.join(self.src_dir, 'gtest-all.cc'))
-                self.main_src = mesonlib.File.from_absolute_file(
-                    os.path.join(self.src_dir, 'gtest_main.cc'))
-                self.src_include_dir = os.path.normpath(os.path.join(self.src_dir, '..'))
-                return True
-        return False
-
-    def get_compile_args(self):
-        arr = []
-        if self.include_dir != '/usr/include':
-            arr.append('-I' + self.include_dir)
-        if hasattr(self, 'src_include_dir'):
-            arr.append('-I' + self.src_include_dir)
-        return arr
-
-    def get_link_args(self):
-        return self.link_args
-
-    def get_version(self):
-        return '1.something_maybe'
-
-    def get_sources(self):
-        return self.sources
-
-    def need_threads(self):
-        return True
-
-class GMockDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gmock', kwargs)
-        # GMock may be a library or just source.
-        # Work with both.
-        self.name = 'gmock'
-        self.libname = 'libgmock.so'
-        trial_dirs = mesonlib.get_library_dirs()
-        gmock_found = False
-        for d in trial_dirs:
-            if os.path.isfile(os.path.join(d, self.libname)):
-                gmock_found = True
-        if gmock_found:
-            self.is_found = True
-            self.compile_args = []
-            self.link_args = ['-lgmock']
-            self.sources = []
-            mlog.log('Dependency GMock found:', mlog.green('YES'), '(prebuilt)')
-            return
-
-        for d in ['/usr/src/googletest/googlemock/src', '/usr/src/gmock/src', '/usr/src/gmock']:
-            if os.path.exists(d):
-                self.is_found = True
-                # Yes, we need both because there are multiple
-                # versions of gmock that do different things.
-                d2 = os.path.normpath(os.path.join(d, '..'))
-                self.compile_args = ['-I' + d, '-I' + d2]
-                self.link_args = []
-                all_src = mesonlib.File.from_absolute_file(os.path.join(d, 'gmock-all.cc'))
-                main_src = mesonlib.File.from_absolute_file(os.path.join(d, 'gmock_main.cc'))
-                if kwargs.get('main', False):
-                    self.sources = [all_src, main_src]
-                else:
-                    self.sources = [all_src]
-                mlog.log('Dependency GMock found:', mlog.green('YES'), '(building self)')
-                return
-
-        mlog.log('Dependency GMock found:', mlog.red('NO'))
-        self.is_found = False
-
-    def get_version(self):
-        return '1.something_maybe'
-
-    def get_compile_args(self):
-        return self.compile_args
-
-    def get_sources(self):
-        return self.sources
-
-    def get_link_args(self):
-        return self.link_args
-
-    def found(self):
-        return self.is_found
-
-class QtBaseDependency(Dependency):
-    def __init__(self, name, env, kwargs):
-        Dependency.__init__(self, name, kwargs)
-        self.name = name
-        self.qtname = name.capitalize()
-        self.qtver = name[-1]
-        if self.qtver == "4":
-            self.qtpkgname = 'Qt'
-        else:
-            self.qtpkgname = self.qtname
-        self.root = '/usr'
-        self.bindir = None
-        self.silent = kwargs.get('silent', False)
-        # We store the value of required here instead of passing it on to
-        # PkgConfigDependency etc because we want to try the qmake-based
-        # fallback as well.
-        self.required = kwargs.pop('required', True)
-        kwargs['required'] = False
-        mods = kwargs.get('modules', [])
-        self.cargs = []
-        self.largs = []
-        self.is_found = False
-        if isinstance(mods, str):
-            mods = [mods]
-        if not mods:
-            raise DependencyException('No ' + self.qtname + '  modules specified.')
-        type_text = 'cross' if env.is_cross_build() else 'native'
-        found_msg = '{} {} {{}} dependency (modules: {}) found:' \
-                    ''.format(self.qtname, type_text, ', '.join(mods))
-        from_text = 'pkg-config'
-
-        # Keep track of the detection methods used, for logging purposes.
-        methods = []
-        # Prefer pkg-config, then fallback to `qmake -query`
-        if DependencyMethods.PKGCONFIG in self.methods:
-            self._pkgconfig_detect(mods, env, kwargs)
-            methods.append('pkgconfig')
-        if not self.is_found and DependencyMethods.QMAKE in self.methods:
-            from_text = self._qmake_detect(mods, env, kwargs)
-            methods.append('qmake-' + self.name)
-            methods.append('qmake')
-        if not self.is_found:
-            # Reset compile args and link args
-            self.cargs = []
-            self.largs = []
-            from_text = '(checked {})'.format(mlog.format_list(methods))
-            self.version = 'none'
-            if self.required:
-                err_msg = '{} {} dependency not found {}' \
-                          ''.format(self.qtname, type_text, from_text)
-                raise DependencyException(err_msg)
-            if not self.silent:
-                mlog.log(found_msg.format(from_text), mlog.red('NO'))
-            return
-        from_text = '`{}`'.format(from_text)
-        if not self.silent:
-            mlog.log(found_msg.format(from_text), mlog.green('YES'))
-
-    def compilers_detect(self):
-        "Detect Qt (4 or 5) moc, uic, rcc in the specified bindir or in PATH"
-        if self.bindir:
-            moc = ExternalProgram(os.path.join(self.bindir, 'moc'), silent=True)
-            uic = ExternalProgram(os.path.join(self.bindir, 'uic'), silent=True)
-            rcc = ExternalProgram(os.path.join(self.bindir, 'rcc'), silent=True)
-        else:
-            # We don't accept unsuffixed 'moc', 'uic', and 'rcc' because they
-            # are sometimes older, or newer versions.
-            moc = ExternalProgram('moc-' + self.name, silent=True)
-            uic = ExternalProgram('uic-' + self.name, silent=True)
-            rcc = ExternalProgram('rcc-' + self.name, silent=True)
-        return moc, uic, rcc
-
-    def _pkgconfig_detect(self, mods, env, kwargs):
-        modules = OrderedDict()
-        for module in mods:
-            modules[module] = PkgConfigDependency(self.qtpkgname + module, env, kwargs)
-        self.is_found = True
-        for m in modules.values():
-            if not m.found():
-                self.is_found = False
-                return
-            self.cargs += m.get_compile_args()
-            self.largs += m.get_link_args()
-        self.version = m.modversion
-        # Try to detect moc, uic, rcc
-        if 'Core' in modules:
-            core = modules['Core']
-        else:
-            corekwargs = {'required': 'false', 'silent': 'true'}
-            core = PkgConfigDependency(self.qtpkgname + 'Core', env, corekwargs)
-        # Used by self.compilers_detect()
-        self.bindir = self.get_pkgconfig_host_bins(core)
-        if not self.bindir:
-            # If exec_prefix is not defined, the pkg-config file is broken
-            prefix = core.get_pkgconfig_variable('exec_prefix')
-            if prefix:
-                self.bindir = os.path.join(prefix, 'bin')
-
-    def _find_qmake(self, qmake, env):
-        # Even when cross-compiling, if we don't get a cross-info qmake, we
-        # fallback to using the qmake in PATH because that's what we used to do
-        if env.is_cross_build():
-            qmake = env.cross_info.config['binaries'].get('qmake', qmake)
-        return ExternalProgram(qmake, silent=True)
-
-    def _qmake_detect(self, mods, env, kwargs):
-        for qmake in ('qmake-' + self.name, 'qmake'):
-            self.qmake = self._find_qmake(qmake, env)
-            if not self.qmake.found():
-                continue
-            # Check that the qmake is for qt5
-            pc, stdo = Popen_safe(self.qmake.get_command() + ['-v'])[0:2]
-            if pc.returncode != 0:
-                continue
-            if not 'Qt version ' + self.qtver in stdo:
-                mlog.log('QMake is not for ' + self.qtname)
-                continue
-            # Found qmake for Qt5!
-            break
-        else:
-            # Didn't find qmake :(
-            return
-        self.version = re.search(self.qtver + '(\.\d+)+', stdo).group(0)
-        # Query library path, header path, and binary path
-        mlog.log("Found qmake:", mlog.bold(self.qmake.get_name()), '(%s)' % self.version)
-        stdo = Popen_safe(self.qmake.get_command() + ['-query'])[1]
-        qvars = {}
-        for line in stdo.split('\n'):
-            line = line.strip()
-            if line == '':
-                continue
-            (k, v) = tuple(line.split(':', 1))
-            qvars[k] = v
-        if mesonlib.is_osx():
-            return self._framework_detect(qvars, mods, kwargs)
-        incdir = qvars['QT_INSTALL_HEADERS']
-        self.cargs.append('-I' + incdir)
-        libdir = qvars['QT_INSTALL_LIBS']
-        # Used by self.compilers_detect()
-        self.bindir = self.get_qmake_host_bins(qvars)
-        self.is_found = True
-        for module in mods:
-            mincdir = os.path.join(incdir, 'Qt' + module)
-            self.cargs.append('-I' + mincdir)
-            if for_windows(env.is_cross_build(), env):
-                libfile = os.path.join(libdir, self.qtpkgname + module + '.lib')
-                if not os.path.isfile(libfile):
-                    # MinGW can link directly to .dll
-                    libfile = os.path.join(self.bindir, self.qtpkgname + module + '.dll')
-                    if not os.path.isfile(libfile):
-                        self.is_found = False
-                        break
-            else:
-                libfile = os.path.join(libdir, 'lib{}{}.so'.format(self.qtpkgname, module))
-                if not os.path.isfile(libfile):
-                    self.is_found = False
-                    break
-            self.largs.append(libfile)
-        return qmake
-
-    def _framework_detect(self, qvars, modules, kwargs):
-        libdir = qvars['QT_INSTALL_LIBS']
-        for m in modules:
-            fname = 'Qt' + m
-            fwdep = ExtraFrameworkDependency(fname, kwargs.get('required', True), libdir, kwargs)
-            self.cargs.append('-F' + libdir)
-            if fwdep.found():
-                self.is_found = True
-                self.cargs += fwdep.get_compile_args()
-                self.largs += fwdep.get_link_args()
-        # Used by self.compilers_detect()
-        self.bindir = self.get_qmake_host_bins(qvars)
-
-    def get_qmake_host_bins(self, qvars):
-        # Prefer QT_HOST_BINS (qt5, correct for cross and native compiling)
-        # but fall back to QT_INSTALL_BINS (qt4)
-        if 'QT_HOST_BINS' in qvars:
-            return qvars['QT_HOST_BINS']
-        else:
-            return qvars['QT_INSTALL_BINS']
-
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_sources(self):
-        return []
-
-    def get_link_args(self):
-        return self.largs
-
-    def get_methods(self):
-        return [DependencyMethods.PKGCONFIG, DependencyMethods.QMAKE]
-
-    def found(self):
-        return self.is_found
-
-    def get_exe_args(self, compiler):
-        # Originally this was -fPIE but nowadays the default
-        # for upstream and distros seems to be -reduce-relocations
-        # which requires -fPIC. This may cause a performance
-        # penalty when using self-built Qt or on platforms
-        # where -fPIC is not required. If this is an issue
-        # for you, patches are welcome.
-        return compiler.get_pic_args()
-
-class Qt5Dependency(QtBaseDependency):
-    def __init__(self, env, kwargs):
-        QtBaseDependency.__init__(self, 'qt5', env, kwargs)
-
-    def get_pkgconfig_host_bins(self, core):
-        return core.get_pkgconfig_variable('host_bins')
-
-class Qt4Dependency(QtBaseDependency):
-    def __init__(self, env, kwargs):
-        QtBaseDependency.__init__(self, 'qt4', env, kwargs)
-
-    def get_pkgconfig_host_bins(self, core):
-        # Only return one bins dir, because the tools are generally all in one
-        # directory for Qt4, in Qt5, they must all be in one directory. Return
-        # the first one found among the bin variables, in case one tool is not
-        # configured to be built.
-        applications = ['moc', 'uic', 'rcc', 'lupdate', 'lrelease']
-        for application in applications:
-            try:
-                return os.path.dirname(core.get_pkgconfig_variable('%s_location' % application))
-            except MesonException:
-                pass
-
-class GnuStepDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gnustep', kwargs)
-        self.required = kwargs.get('required', True)
-        self.modules = kwargs.get('modules', [])
-        self.detect()
-
-    def detect(self):
-        self.confprog = 'gnustep-config'
-        try:
-            gp = Popen_safe([self.confprog, '--help'])[0]
-        except (FileNotFoundError, PermissionError):
-            self.args = None
-            mlog.log('Dependency GnuStep found:', mlog.red('NO'), '(no gnustep-config)')
-            return
-        if gp.returncode != 0:
-            self.args = None
-            mlog.log('Dependency GnuStep found:', mlog.red('NO'))
-            return
-        if 'gui' in self.modules:
-            arg = '--gui-libs'
-        else:
-            arg = '--base-libs'
-        fp, flagtxt, flagerr = Popen_safe([self.confprog, '--objc-flags'])
-        if fp.returncode != 0:
-            raise DependencyException('Error getting objc-args: %s %s' % (flagtxt, flagerr))
-        args = flagtxt.split()
-        self.args = self.filter_arsg(args)
-        fp, libtxt, liberr = Popen_safe([self.confprog, arg])
-        if fp.returncode != 0:
-            raise DependencyException('Error getting objc-lib args: %s %s' % (libtxt, liberr))
-        self.libs = self.weird_filter(libtxt.split())
-        self.version = self.detect_version()
-        mlog.log('Dependency', mlog.bold('GnuStep'), 'found:',
-                 mlog.green('YES'), self.version)
-
-    def weird_filter(self, elems):
-        """When building packages, the output of the enclosing Make
-is sometimes mixed among the subprocess output. I have no idea
-why. As a hack filter out everything that is not a flag."""
-        return [e for e in elems if e.startswith('-')]
-
-    def filter_arsg(self, args):
-        """gnustep-config returns a bunch of garbage args such
-        as -O2 and so on. Drop everything that is not needed."""
-        result = []
-        for f in args:
-            if f.startswith('-D') \
-                    or f.startswith('-f') \
-                    or f.startswith('-I') \
-                    or f == '-pthread' \
-                    or (f.startswith('-W') and not f == '-Wall'):
-                result.append(f)
-        return result
-
-    def detect_version(self):
-        gmake = self.get_variable('GNUMAKE')
-        makefile_dir = self.get_variable('GNUSTEP_MAKEFILES')
-        # This Makefile has the GNUStep version set
-        base_make = os.path.join(makefile_dir, 'Additional', 'base.make')
-        # Print the Makefile variable passed as the argument. For instance, if
-        # you run the make target `print-SOME_VARIABLE`, this will print the
-        # value of the variable `SOME_VARIABLE`.
-        printver = "print-%:\n\t@echo '$($*)'"
-        env = os.environ.copy()
-        # See base.make to understand why this is set
-        env['FOUNDATION_LIB'] = 'gnu'
-        p, o, e = Popen_safe([gmake, '-f', '-', '-f', base_make,
-                              'print-GNUSTEP_BASE_VERSION'],
-                             env=env, write=printver, stdin=subprocess.PIPE)
-        version = o.strip()
-        if not version:
-            mlog.debug("Couldn't detect GNUStep version, falling back to '1'")
-            # Fallback to setting some 1.x version
-            version = '1'
-        return version
-
-    def get_variable(self, var):
-        p, o, e = Popen_safe([self.confprog, '--variable=' + var])
-        if p.returncode != 0 and self.required:
-            raise DependencyException('{!r} for variable {!r} failed to run'
-                                      ''.format(self.confprog, var))
-        return o.strip()
-
-    def found(self):
-        return self.args is not None
-
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        if self.args is None:
-            return []
-        return self.args
-
-    def get_link_args(self):
-        return self.libs
-
-class AppleFrameworks(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'appleframeworks', kwargs)
-        modules = kwargs.get('modules', [])
-        if isinstance(modules, str):
-            modules = [modules]
-        if not modules:
-            raise DependencyException("AppleFrameworks dependency requires at least one module.")
-        self.frameworks = modules
-
-    def get_link_args(self):
-        args = []
-        for f in self.frameworks:
-            args.append('-framework')
-            args.append(f)
-        return args
-
-    def found(self):
-        return mesonlib.is_osx()
-
-    def get_version(self):
-        return 'unknown'
-
-class GLDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gl', kwargs)
-        self.is_found = False
-        self.cargs = []
-        self.linkargs = []
-        if DependencyMethods.PKGCONFIG in self.methods:
-            try:
-                pcdep = PkgConfigDependency('gl', environment, kwargs)
-                if pcdep.found():
-                    self.type_name = 'pkgconfig'
-                    self.is_found = True
-                    self.cargs = pcdep.get_compile_args()
-                    self.linkargs = pcdep.get_link_args()
-                    self.version = pcdep.get_version()
-                    return
-            except Exception:
-                pass
-        if DependencyMethods.SYSTEM in self.methods:
-            if mesonlib.is_osx():
-                self.is_found = True
-                self.linkargs = ['-framework', 'OpenGL']
-                self.version = '1' # FIXME
-                return
-            if mesonlib.is_windows():
-                self.is_found = True
-                self.linkargs = ['-lopengl32']
-                self.version = '1' # FIXME: unfixable?
-                return
-
-    def get_link_args(self):
-        return self.linkargs
-
-    def get_version(self):
-        return self.version
-
-    def get_methods(self):
-        if mesonlib.is_osx() or mesonlib.is_windows():
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM]
-        else:
-            return [DependencyMethods.PKGCONFIG]
-
-# There are three different ways of depending on SDL2:
-# sdl2-config, pkg-config and OSX framework
-class SDL2Dependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'sdl2', kwargs)
-        self.is_found = False
-        self.cargs = []
-        self.linkargs = []
-        if DependencyMethods.PKGCONFIG in self.methods:
-            try:
-                pcdep = PkgConfigDependency('sdl2', environment, kwargs)
-                if pcdep.found():
-                    self.type_name = 'pkgconfig'
-                    self.is_found = True
-                    self.cargs = pcdep.get_compile_args()
-                    self.linkargs = pcdep.get_link_args()
-                    self.version = pcdep.get_version()
-                    return
-            except Exception as e:
-                mlog.debug('SDL 2 not found via pkgconfig. Trying next, error was:', str(e))
-                pass
-        if DependencyMethods.SDLCONFIG in self.methods:
-            sdlconf = shutil.which('sdl2-config')
-            if sdlconf:
-                stdo = Popen_safe(['sdl2-config', '--cflags'])[1]
-                self.cargs = stdo.strip().split()
-                stdo = Popen_safe(['sdl2-config', '--libs'])[1]
-                self.linkargs = stdo.strip().split()
-                stdo = Popen_safe(['sdl2-config', '--version'])[1]
-                self.version = stdo.strip()
-                self.is_found = True
-                mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.green('YES'),
-                         self.version, '(%s)' % sdlconf)
-                return
-            mlog.debug('Could not find sdl2-config binary, trying next.')
-        if DependencyMethods.EXTRAFRAMEWORK in self.methods:
-            if mesonlib.is_osx():
-                fwdep = ExtraFrameworkDependency('sdl2', kwargs.get('required', True), None, kwargs)
-                if fwdep.found():
-                    self.is_found = True
-                    self.cargs = fwdep.get_compile_args()
-                    self.linkargs = fwdep.get_link_args()
-                    self.version = '2' # FIXME
-                    return
-            mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.red('NO'))
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.linkargs
-
-    def found(self):
-        return self.is_found
-
-    def get_version(self):
-        return self.version
-
-    def get_methods(self):
-        if mesonlib.is_osx():
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG, DependencyMethods.EXTRAFRAMEWORK]
-        else:
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG]
-
-class ExtraFrameworkDependency(Dependency):
-    def __init__(self, name, required, path, kwargs):
-        Dependency.__init__(self, 'extraframeworks', kwargs)
-        self.name = None
-        self.detect(name, path)
-        if self.found():
-            mlog.log('Dependency', mlog.bold(name), 'found:', mlog.green('YES'),
-                     os.path.join(self.path, self.name))
-        else:
-            mlog.log('Dependency', name, 'found:', mlog.red('NO'))
-
-    def detect(self, name, path):
-        lname = name.lower()
-        if path is None:
-            paths = ['/Library/Frameworks']
-        else:
-            paths = [path]
-        for p in paths:
-            for d in os.listdir(p):
-                fullpath = os.path.join(p, d)
-                if lname != d.split('.')[0].lower():
-                    continue
-                if not stat.S_ISDIR(os.stat(fullpath).st_mode):
-                    continue
-                self.path = p
-                self.name = d
-                return
-
-    def get_compile_args(self):
-        if self.found():
-            return ['-I' + os.path.join(self.path, self.name, 'Headers')]
-        return []
-
-    def get_link_args(self):
-        if self.found():
-            return ['-F' + self.path, '-framework', self.name.split('.')[0]]
-        return []
-
-    def found(self):
-        return self.name is not None
-
-    def get_version(self):
-        return 'unknown'
-
-class ThreadDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        super().__init__('threads', {})
-        self.name = 'threads'
-        self.is_found = True
-        mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
-
-    def need_threads(self):
-        return True
-
-    def get_version(self):
-        return 'unknown'
-
-class Python3Dependency(Dependency):
-    def __init__(self, environment, kwargs):
-        super().__init__('python3', kwargs)
-        self.name = 'python3'
-        self.is_found = False
-        # We can only be sure that it is Python 3 at this point
-        self.version = '3'
-        if DependencyMethods.PKGCONFIG in self.methods:
-            try:
-                pkgdep = PkgConfigDependency('python3', environment, kwargs)
-                if pkgdep.found():
-                    self.cargs = pkgdep.cargs
-                    self.libs = pkgdep.libs
-                    self.version = pkgdep.get_version()
-                    self.is_found = True
-                    return
-            except Exception:
-                pass
-        if not self.is_found:
-            if mesonlib.is_windows() and DependencyMethods.SYSCONFIG in self.methods:
-                self._find_libpy3_windows(environment)
-            elif mesonlib.is_osx() and DependencyMethods.EXTRAFRAMEWORK in self.methods:
-                # In OSX the Python 3 framework does not have a version
-                # number in its name.
-                fw = ExtraFrameworkDependency('python', False, None, kwargs)
-                if fw.found():
-                    self.cargs = fw.get_compile_args()
-                    self.libs = fw.get_link_args()
-                    self.is_found = True
-        if self.is_found:
-            mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
-        else:
-            mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.red('NO'))
-
-    def _find_libpy3_windows(self, env):
-        '''
-        Find python3 libraries on Windows and also verify that the arch matches
-        what we are building for.
-        '''
-        pyarch = sysconfig.get_platform()
-        arch = detect_cpu_family(env.coredata.compilers)
-        if arch == 'x86':
-            arch = '32'
-        elif arch == 'x86_64':
-            arch = '64'
-        else:
-            # We can't cross-compile Python 3 dependencies on Windows yet
-            mlog.log('Unknown architecture {!r} for'.format(arch),
-                     mlog.bold(self.name))
-            self.is_found = False
-            return
-        # Pyarch ends in '32' or '64'
-        if arch != pyarch[-2:]:
-            mlog.log('Need', mlog.bold(self.name),
-                     'for {}-bit, but found {}-bit'.format(arch, pyarch[-2:]))
-            self.is_found = False
-            return
-        inc = sysconfig.get_path('include')
-        platinc = sysconfig.get_path('platinclude')
-        self.cargs = ['-I' + inc]
-        if inc != platinc:
-            self.cargs.append('-I' + platinc)
-        # Nothing exposes this directly that I coulf find
-        basedir = sysconfig.get_config_var('base')
-        vernum = sysconfig.get_config_var('py_version_nodot')
-        self.libs = ['-L{}/libs'.format(basedir),
-                     '-lpython{}'.format(vernum)]
-        self.version = sysconfig.get_config_var('py_version_short')
-        self.is_found = True
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
-    def get_methods(self):
-        if mesonlib.is_windows():
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSCONFIG]
-        elif mesonlib.is_osx():
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.EXTRAFRAMEWORK]
-        else:
-            return [DependencyMethods.PKGCONFIG]
-
-    def get_version(self):
-        return self.version
-
-class ValgrindDependency(PkgConfigDependency):
-
-    def __init__(self, environment, kwargs):
-        PkgConfigDependency.__init__(self, 'valgrind', environment, kwargs)
-
-    def get_link_args(self):
-        return []
-
-class LLVMDependency(Dependency):
-    """LLVM dependency.
-
-    LLVM uses a special tool, llvm-config, which has arguments for getting
-    c args, cxx args, and ldargs as well as version.
-    """
-
-    # Ordered list of llvm-config binaries to try. Start with base, then try
-    # newest back to oldest (3.5 is abitrary), and finally the devel version.
-    llvm_config_bins = [
-        'llvm-config', 'llvm-config-4.0', 'llvm-config-3.9', 'llvm-config39',
-        'llvm-config-3.8', 'llvm-config38', 'llvm-config-3.7', 'llvm-config37',
-        'llvm-config-3.6', 'llvm-config36', 'llvm-config-3.5', 'llvm-config35',
-        'llvm-config-devel',
-    ]
-    llvmconfig = None
-    _llvmconfig_found = False
-    __best_found = None
-    __cpp_blacklist = {'-DNDEBUG'}
-
-    def __init__(self, environment, kwargs):
-        super().__init__('llvm-config', kwargs)
-        # It's necessary for LLVM <= 3.8 to use the C++ linker. For 3.9 and 4.0
-        # the C linker works fine if only using the C API.
-        self.language = 'cpp'
-        self.cargs = []
-        self.libs = []
-        self.modules = []
-
-        required = kwargs.get('required', True)
-        req_version = kwargs.get('version', None)
-        if self.llvmconfig is None:
-            self.check_llvmconfig(req_version)
-        if not self._llvmconfig_found:
-            if self.__best_found is not None:
-                mlog.log('found {!r} but need:'.format(self.__best_found),
-                         req_version)
-            else:
-                mlog.log("No llvm-config found; can't detect dependency")
-            mlog.log('Dependency LLVM found:', mlog.red('NO'))
-            if required:
-                raise DependencyException('Dependency LLVM not found')
-            return
-
-        p, out, err = Popen_safe([self.llvmconfig, '--version'])
-        if p.returncode != 0:
-            mlog.debug('stdout: {}\nstderr: {}'.format(out, err))
-            if required:
-                raise DependencyException('Dependency LLVM not found')
-            return
-        else:
-            self.version = out.strip()
-            mlog.log('Dependency LLVM found:', mlog.green('YES'))
-            self.is_found = True
-
-            p, out = Popen_safe(
-                [self.llvmconfig, '--libs', '--ldflags', '--system-libs'])[:2]
-            if p.returncode != 0:
-                raise DependencyException('Could not generate libs for LLVM.')
-            self.libs = shlex.split(out)
-
-            p, out = Popen_safe([self.llvmconfig, '--cppflags'])[:2]
-            if p.returncode != 0:
-                raise DependencyException('Could not generate includedir for LLVM.')
-            self.cargs = list(mesonlib.OrderedSet(shlex.split(out)).difference(self.__cpp_blacklist))
-
-            p, out = Popen_safe([self.llvmconfig, '--components'])[:2]
-            if p.returncode != 0:
-                raise DependencyException('Could not generate modules for LLVM.')
-            self.modules = shlex.split(out)
-
-        modules = mesonlib.stringlistify(kwargs.get('modules', []))
-        for mod in modules:
-            if mod not in self.modules:
-                mlog.log('LLVM module', mod, 'found:', mlog.red('NO'))
-                self.is_found = False
-                if required:
-                    raise DependencyException(
-                        'Could not find required LLVM Component: {}'.format(mod))
-            else:
-                mlog.log('LLVM module', mod, 'found:', mlog.green('YES'))
-
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
-    @classmethod
-    def check_llvmconfig(cls, version_req):
-        """Try to find the highest version of llvm-config."""
-        for llvmconfig in cls.llvm_config_bins:
-            try:
-                p, out = Popen_safe([llvmconfig, '--version'])[0:2]
-                out = out.strip()
-                if p.returncode != 0:
-                    continue
-                if version_req:
-                    if version_compare(out, version_req, strict=True):
-                        if cls.__best_found and version_compare(out, '<={}'.format(cls.__best_found), strict=True):
-                            continue
-                        cls.__best_found = out
-                        cls.llvmconfig = llvmconfig
-                else:
-                    # If no specific version is requested use the first version
-                    # found, since that should be the best.
-                    cls.__best_found = out
-                    cls.llvmconfig = llvmconfig
-                    break
-            except (FileNotFoundError, PermissionError):
-                pass
-        if cls.__best_found:
-            mlog.log('Found llvm-config:',
-                     mlog.bold(shutil.which(cls.llvmconfig)),
-                     '({})'.format(out.strip()))
-            cls._llvmconfig_found = True
-        else:
-            cls.llvmconfig = False
-
-    def need_threads(self):
-        return True
-
-
-def get_dep_identifier(name, kwargs, want_cross):
-    # Need immutable objects since the identifier will be used as a dict key
-    version_reqs = flatten(kwargs.get('version', []))
-    if isinstance(version_reqs, list):
-        version_reqs = frozenset(version_reqs)
-    identifier = (name, version_reqs, want_cross)
-    for key, value in kwargs.items():
-        # 'version' is embedded above as the second element for easy access
-        # 'native' is handled above with `want_cross`
-        # 'required' is irrelevant for caching; the caller handles it separately
-        # 'fallback' subprojects cannot be cached -- they must be initialized
-        if key in ('version', 'native', 'required', 'fallback',):
-            continue
-        # All keyword arguments are strings, ints, or lists (or lists of lists)
-        if isinstance(value, list):
-            value = frozenset(flatten(value))
-        identifier += (key, value)
-    return identifier
-
-def find_external_dependency(name, environment, kwargs):
-    required = kwargs.get('required', True)
-    if not isinstance(required, bool):
-        raise DependencyException('Keyword "required" must be a boolean.')
-    if not isinstance(kwargs.get('method', ''), str):
-        raise DependencyException('Keyword "method" must be a string.')
-    lname = name.lower()
-    if lname in packages:
-        dep = packages[lname](environment, kwargs)
-        if required and not dep.found():
-            raise DependencyException('Dependency "%s" not found' % name)
-        return dep
-    pkg_exc = None
-    pkgdep = None
-    try:
-        pkgdep = PkgConfigDependency(name, environment, kwargs)
-        if pkgdep.found():
-            return pkgdep
-    except Exception as e:
-        pkg_exc = e
-    if mesonlib.is_osx():
-        fwdep = ExtraFrameworkDependency(name, required, None, kwargs)
-        if required and not fwdep.found():
-            m = 'Dependency {!r} not found, tried Extra Frameworks ' \
-                'and Pkg-Config:\n\n' + str(pkg_exc)
-            raise DependencyException(m.format(name))
-        return fwdep
-    if pkg_exc is not None:
-        raise pkg_exc
-    mlog.log('Dependency', mlog.bold(name), 'found:', mlog.red('NO'))
-    return pkgdep
-
-# This has to be at the end so the classes it references
-# are defined.
-packages = {'boost': BoostDependency,
-            'gtest': GTestDependency,
-            'gmock': GMockDependency,
-            'qt5': Qt5Dependency,
-            'qt4': Qt4Dependency,
-            'gnustep': GnuStepDependency,
-            'appleframeworks': AppleFrameworks,
-            'wxwidgets': WxDependency,
-            'sdl2': SDL2Dependency,
-            'gl': GLDependency,
-            'threads': ThreadDependency,
-            'python3': Python3Dependency,
-            'valgrind': ValgrindDependency,
-            'llvm': LLVMDependency,
-            }
diff --git a/mesonbuild/dependencies/__init__.py b/mesonbuild/dependencies/__init__.py
new file mode 100644
index 0000000..ec11152
--- /dev/null
+++ b/mesonbuild/dependencies/__init__.py
@@ -0,0 +1,46 @@
+# Copyright 2017 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .base import (  # noqa: F401
+    Dependency, DependencyException, DependencyMethods, ExternalProgram, ExternalLibrary, ExtraFrameworkDependency,
+    InternalDependency, PkgConfigDependency, find_external_dependency, get_dep_identifier, packages)
+from .dev import GMockDependency, GTestDependency, LLVMDependency, ValgrindDependency
+from .misc import BoostDependency, Python3Dependency, ThreadDependency
+from .platform import AppleFrameworks
+from .ui import GLDependency, GnuStepDependency, Qt4Dependency, Qt5Dependency, SDL2Dependency, WxDependency
+
+
+packages.update({
+    # From dev:
+    'gtest': GTestDependency,
+    'gmock': GMockDependency,
+    'llvm': LLVMDependency,
+    'valgrind': ValgrindDependency,
+
+    # From misc:
+    'boost': BoostDependency,
+    'python3': Python3Dependency,
+    'threads': ThreadDependency,
+
+    # From platform:
+    'appleframeworks': AppleFrameworks,
+
+    # From ui:
+    'gl': GLDependency,
+    'gnustep': GnuStepDependency,
+    'qt4': Qt4Dependency,
+    'qt5': Qt5Dependency,
+    'sdl2': SDL2Dependency,
+    'wxwidgets': WxDependency,
+})
diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
new file mode 100644
index 0000000..b934ddf
--- /dev/null
+++ b/mesonbuild/dependencies/base.py
@@ -0,0 +1,641 @@
+# Copyright 2013-2017 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file contains the detection logic for external dependencies.
+# Custom logic for several other packages are in separate files.
+
+import os
+import shutil
+import stat
+import sys
+from enum import Enum
+
+from .. import mlog
+from .. import mesonlib
+from ..mesonlib import MesonException, Popen_safe, flatten, version_compare_many
+
+
+# This must be defined in this file to avoid cyclical references.
+packages = {}
+
+
+class DependencyException(MesonException):
+    '''Exceptions raised while trying to find dependencies'''
+
+
+class DependencyMethods(Enum):
+    # Auto means to use whatever dependency checking mechanisms in whatever order meson thinks is best.
+    AUTO = 'auto'
+    PKGCONFIG = 'pkg-config'
+    QMAKE = 'qmake'
+    # Just specify the standard link arguments, assuming the operating system provides the library.
+    SYSTEM = 'system'
+    # Detect using sdl2-config
+    SDLCONFIG = 'sdlconfig'
+    # This is only supported on OSX - search the frameworks directory by name.
+    EXTRAFRAMEWORK = 'extraframework'
+    # Detect using the sysconfig module.
+    SYSCONFIG = 'sysconfig'
+
+
+class Dependency:
+    def __init__(self, type_name, kwargs):
+        self.name = "null"
+        self.language = None
+        self.is_found = False
+        self.type_name = type_name
+        method = DependencyMethods(kwargs.get('method', 'auto'))
+
+        # Set the detection method. If the method is set to auto, use any available method.
+        # If method is set to a specific string, allow only that detection method.
+        if method == DependencyMethods.AUTO:
+            self.methods = self.get_methods()
+        elif method in self.get_methods():
+            self.methods = [method]
+        else:
+            raise MesonException(
+                'Unsupported detection method: {}, allowed methods are {}'.format(
+                    method.value,
+                    mlog.format_list(map(lambda x: x.value, [DependencyMethods.AUTO] + self.get_methods()))))
+
+    def __repr__(self):
+        s = '<{0} {1}: {2}>'
+        return s.format(self.__class__.__name__, self.name, self.is_found)
+
+    def get_compile_args(self):
+        return []
+
+    def get_link_args(self):
+        return []
+
+    def found(self):
+        return self.is_found
+
+    def get_sources(self):
+        """Source files that need to be added to the target.
+        As an example, gtest-all.cc when using GTest."""
+        return []
+
+    def get_methods(self):
+        return [DependencyMethods.AUTO]
+
+    def get_name(self):
+        return self.name
+
+    def get_exe_args(self, compiler):
+        return []
+
+    def need_threads(self):
+        return False
+
+    def get_pkgconfig_variable(self, variable_name):
+        raise MesonException('Tried to get a pkg-config variable from a non-pkgconfig dependency.')
+
+
+class InternalDependency(Dependency):
+    def __init__(self, version, incdirs, compile_args, link_args, libraries, sources, ext_deps):
+        super().__init__('internal', {})
+        self.version = version
+        self.is_found = True
+        self.include_directories = incdirs
+        self.compile_args = compile_args
+        self.link_args = link_args
+        self.libraries = libraries
+        self.sources = sources
+        self.ext_deps = ext_deps
+
+    def get_compile_args(self):
+        return self.compile_args
+
+    def get_link_args(self):
+        return self.link_args
+
+    def get_version(self):
+        return self.version
+
+
+class PkgConfigDependency(Dependency):
+    # The class's copy of the pkg-config path. Avoids having to search for it
+    # multiple times in the same Meson invocation.
+    class_pkgbin = None
+
+    def __init__(self, name, environment, kwargs):
+        Dependency.__init__(self, 'pkgconfig', kwargs)
+        self.is_libtool = False
+        self.version_reqs = kwargs.get('version', None)
+        self.required = kwargs.get('required', True)
+        self.static = kwargs.get('static', False)
+        self.silent = kwargs.get('silent', False)
+        if not isinstance(self.static, bool):
+            raise DependencyException('Static keyword must be boolean')
+        # Store a copy of the pkg-config path on the object itself so it is
+        # stored in the pickled coredata and recovered.
+        self.pkgbin = None
+        self.cargs = []
+        self.libs = []
+        if 'native' in kwargs and environment.is_cross_build():
+            self.want_cross = not kwargs['native']
+        else:
+            self.want_cross = environment.is_cross_build()
+        self.name = name
+        self.modversion = 'none'
+
+        # When finding dependencies for cross-compiling, we don't care about
+        # the 'native' pkg-config
+        if self.want_cross:
+            if 'pkgconfig' not in environment.cross_info.config['binaries']:
+                if self.required:
+                    raise DependencyException('Pkg-config binary missing from cross file')
+            else:
+                pkgname = environment.cross_info.config['binaries']['pkgconfig']
+                potential_pkgbin = ExternalProgram(pkgname, silent=True)
+                if potential_pkgbin.found():
+                    # FIXME, we should store all pkg-configs in ExternalPrograms.
+                    # However that is too destabilizing a change to do just before release.
+                    self.pkgbin = potential_pkgbin.get_command()[0]
+                    PkgConfigDependency.class_pkgbin = self.pkgbin
+                else:
+                    mlog.debug('Cross pkg-config %s not found.' % potential_pkgbin.name)
+        # Only search for the native pkg-config the first time and
+        # store the result in the class definition
+        elif PkgConfigDependency.class_pkgbin is None:
+            self.pkgbin = self.check_pkgconfig()
+            PkgConfigDependency.class_pkgbin = self.pkgbin
+        else:
+            self.pkgbin = PkgConfigDependency.class_pkgbin
+
+        self.is_found = False
+        if not self.pkgbin:
+            if self.required:
+                raise DependencyException('Pkg-config not found.')
+            return
+        if self.want_cross:
+            self.type_string = 'Cross'
+        else:
+            self.type_string = 'Native'
+
+        mlog.debug('Determining dependency {!r} with pkg-config executable '
+                   '{!r}'.format(name, self.pkgbin))
+        ret, self.modversion = self._call_pkgbin(['--modversion', name])
+        if ret != 0:
+            if self.required:
+                raise DependencyException('{} dependency {!r} not found'
+                                          ''.format(self.type_string, name))
+            return
+        found_msg = [self.type_string + ' dependency', mlog.bold(name), 'found:']
+        if self.version_reqs is None:
+            self.is_found = True
+        else:
+            if not isinstance(self.version_reqs, (str, list)):
+                raise DependencyException('Version argument must be string or list.')
+            if isinstance(self.version_reqs, str):
+                self.version_reqs = [self.version_reqs]
+            (self.is_found, not_found, found) = \
+                version_compare_many(self.modversion, self.version_reqs)
+            if not self.is_found:
+                found_msg += [mlog.red('NO'),
+                              'found {!r} but need:'.format(self.modversion),
+                              ', '.join(["'{}'".format(e) for e in not_found])]
+                if found:
+                    found_msg += ['; matched:',
+                                  ', '.join(["'{}'".format(e) for e in found])]
+                if not self.silent:
+                    mlog.log(*found_msg)
+                if self.required:
+                    m = 'Invalid version of dependency, need {!r} {!r} found {!r}.'
+                    raise DependencyException(m.format(name, not_found, self.modversion))
+                return
+        found_msg += [mlog.green('YES'), self.modversion]
+        # Fetch cargs to be used while using this dependency
+        self._set_cargs()
+        # Fetch the libraries and library paths needed for using this
+        self._set_libs()
+        # Print the found message only at the very end because fetching cflags
+        # and libs can also fail if other needed pkg-config files aren't found.
+        if not self.silent:
+            mlog.log(*found_msg)
+
+    def __repr__(self):
+        s = '<{0} {1}: {2} {3}>'
+        return s.format(self.__class__.__name__, self.name, self.is_found,
+                        self.version_reqs)
+
+    def _call_pkgbin(self, args):
+        p, out = Popen_safe([self.pkgbin] + args, env=os.environ)[0:2]
+        return p.returncode, out.strip()
+
+    def _set_cargs(self):
+        ret, out = self._call_pkgbin(['--cflags', self.name])
+        if ret != 0:
+            raise DependencyException('Could not generate cargs for %s:\n\n%s' %
+                                      (self.name, out))
+        self.cargs = out.split()
+
+    def _set_libs(self):
+        libcmd = [self.name, '--libs']
+        if self.static:
+            libcmd.append('--static')
+        ret, out = self._call_pkgbin(libcmd)
+        if ret != 0:
+            raise DependencyException('Could not generate libs for %s:\n\n%s' %
+                                      (self.name, out))
+        self.libs = []
+        for lib in out.split():
+            if lib.endswith(".la"):
+                shared_libname = self.extract_libtool_shlib(lib)
+                shared_lib = os.path.join(os.path.dirname(lib), shared_libname)
+                if not os.path.exists(shared_lib):
+                    shared_lib = os.path.join(os.path.dirname(lib), ".libs", shared_libname)
+
+                if not os.path.exists(shared_lib):
+                    raise DependencyException('Got a libtools specific "%s" dependencies'
+                                              'but we could not compute the actual shared'
+                                              'library path' % lib)
+                lib = shared_lib
+                self.is_libtool = True
+            self.libs.append(lib)
+
+    def get_pkgconfig_variable(self, variable_name):
+        ret, out = self._call_pkgbin(['--variable=' + variable_name, self.name])
+        variable = ''
+        if ret != 0:
+            if self.required:
+                raise DependencyException('%s dependency %s not found.' %
+                                          (self.type_string, self.name))
+        else:
+            variable = out.strip()
+        mlog.debug('Got pkgconfig variable %s : %s' % (variable_name, variable))
+        return variable
+
+    def get_modversion(self):
+        return self.modversion
+
+    def get_version(self):
+        return self.modversion
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.libs
+
+    def get_methods(self):
+        return [DependencyMethods.PKGCONFIG]
+
+    def check_pkgconfig(self):
+        evar = 'PKG_CONFIG'
+        if evar in os.environ:
+            pkgbin = os.environ[evar].strip()
+        else:
+            pkgbin = 'pkg-config'
+        try:
+            p, out = Popen_safe([pkgbin, '--version'])[0:2]
+            if p.returncode != 0:
+                # Set to False instead of None to signify that we've already
+                # searched for it and not found it
+                pkgbin = False
+        except (FileNotFoundError, PermissionError):
+            pkgbin = False
+        if pkgbin and not os.path.isabs(pkgbin) and shutil.which(pkgbin):
+            # Sometimes shutil.which fails where Popen succeeds, so
+            # only find the abs path if it can be found by shutil.which
+            pkgbin = shutil.which(pkgbin)
+        if not self.silent:
+            if pkgbin:
+                mlog.log('Found pkg-config:', mlog.bold(pkgbin),
+                         '(%s)' % out.strip())
+            else:
+                mlog.log('Found Pkg-config:', mlog.red('NO'))
+        return pkgbin
+
+    def found(self):
+        return self.is_found
+
+    def extract_field(self, la_file, fieldname):
+        with open(la_file) as f:
+            for line in f:
+                arr = line.strip().split('=')
+                if arr[0] == fieldname:
+                    return arr[1][1:-1]
+        return None
+
+    def extract_dlname_field(self, la_file):
+        return self.extract_field(la_file, 'dlname')
+
+    def extract_libdir_field(self, la_file):
+        return self.extract_field(la_file, 'libdir')
+
+    def extract_libtool_shlib(self, la_file):
+        '''
+        Returns the path to the shared library
+        corresponding to this .la file
+        '''
+        dlname = self.extract_dlname_field(la_file)
+        if dlname is None:
+            return None
+
+        # Darwin uses absolute paths where possible; since the libtool files never
+        # contain absolute paths, use the libdir field
+        if mesonlib.is_osx():
+            dlbasename = os.path.basename(dlname)
+            libdir = self.extract_libdir_field(la_file)
+            if libdir is None:
+                return dlbasename
+            return os.path.join(libdir, dlbasename)
+        # From the comments in extract_libtool(), older libtools had
+        # a path rather than the raw dlname
+        return os.path.basename(dlname)
+
+
+class ExternalProgram:
+    windows_exts = ('exe', 'msc', 'com', 'bat')
+
+    def __init__(self, name, command=None, silent=False, search_dir=None):
+        self.name = name
+        if command is not None:
+            if not isinstance(command, list):
+                self.command = [command]
+            else:
+                self.command = command
+        else:
+            self.command = self._search(name, search_dir)
+        if not silent:
+            if self.found():
+                mlog.log('Program', mlog.bold(name), 'found:', mlog.green('YES'),
+                         '(%s)' % ' '.join(self.command))
+            else:
+                mlog.log('Program', mlog.bold(name), 'found:', mlog.red('NO'))
+
+    def __repr__(self):
+        r = '<{} {!r} -> {!r}>'
+        return r.format(self.__class__.__name__, self.name, self.command)
+
+    @staticmethod
+    def _shebang_to_cmd(script):
+        """
+        Check if the file has a shebang and manually parse it to figure out
+        the interpreter to use. This is useful if the script is not executable
+        or if we're on Windows (which does not understand shebangs).
+        """
+        try:
+            with open(script) as f:
+                first_line = f.readline().strip()
+            if first_line.startswith('#!'):
+                commands = first_line[2:].split('#')[0].strip().split()
+                if mesonlib.is_windows():
+                    # Windows does not have UNIX paths so remove them,
+                    # but don't remove Windows paths
+                    if commands[0].startswith('/'):
+                        commands[0] = commands[0].split('/')[-1]
+                    if len(commands) > 0 and commands[0] == 'env':
+                        commands = commands[1:]
+                    # Windows does not ship python3.exe, but we know the path to it
+                    if len(commands) > 0 and commands[0] == 'python3':
+                        commands[0] = sys.executable
+                return commands + [script]
+        except Exception:
+            pass
+        return False
+
+    def _is_executable(self, path):
+        suffix = os.path.splitext(path)[-1].lower()[1:]
+        if mesonlib.is_windows():
+            if suffix in self.windows_exts:
+                return True
+        elif os.access(path, os.X_OK):
+            return not os.path.isdir(path)
+        return False
+
+    def _search_dir(self, name, search_dir):
+        if search_dir is None:
+            return False
+        trial = os.path.join(search_dir, name)
+        if os.path.exists(trial):
+            if self._is_executable(trial):
+                return [trial]
+            # Now getting desperate. Maybe it is a script file that is
+            # a) not chmodded executable, or
+            # b) we are on windows so they can't be directly executed.
+            return self._shebang_to_cmd(trial)
+        else:
+            if mesonlib.is_windows():
+                for ext in self.windows_exts:
+                    trial_ext = '{}.{}'.format(trial, ext)
+                    if os.path.exists(trial_ext):
+                        return [trial_ext]
+        return False
+
+    def _search(self, name, search_dir):
+        '''
+        Search in the specified dir for the specified executable by name
+        and if not found search in PATH
+        '''
+        commands = self._search_dir(name, search_dir)
+        if commands:
+            return commands
+        # Do a standard search in PATH
+        command = shutil.which(name)
+        if not mesonlib.is_windows():
+            # On UNIX-like platforms, shutil.which() is enough to find
+            # all executables whether in PATH or with an absolute path
+            return [command]
+        # HERE BEGINS THE TERROR OF WINDOWS
+        if command:
+            # On Windows, even if the PATH search returned a full path, we can't be
+            # sure that it can be run directly if it's not a native executable.
+            # For instance, interpreted scripts sometimes need to be run explicitly
+            # with an interpreter if the file association is not done properly.
+            name_ext = os.path.splitext(command)[1]
+            if name_ext[1:].lower() in self.windows_exts:
+                # Good, it can be directly executed
+                return [command]
+            # Try to extract the interpreter from the shebang
+            commands = self._shebang_to_cmd(command)
+            if commands:
+                return commands
+        else:
+            # Maybe the name is an absolute path to a native Windows
+            # executable, but without the extension. This is technically wrong,
+            # but many people do it because it works in the MinGW shell.
+            if os.path.isabs(name):
+                for ext in self.windows_exts:
+                    command = '{}.{}'.format(name, ext)
+                    if os.path.exists(command):
+                        return [command]
+            # On Windows, interpreted scripts must have an extension otherwise they
+            # cannot be found by a standard PATH search. So we do a custom search
+            # where we manually search for a script with a shebang in PATH.
+            search_dirs = os.environ.get('PATH', '').split(';')
+            for search_dir in search_dirs:
+                commands = self._search_dir(name, search_dir)
+                if commands:
+                    return commands
+        return [None]
+
+    def found(self):
+        return self.command[0] is not None
+
+    def get_command(self):
+        return self.command[:]
+
+    def get_path(self):
+        if self.found():
+            # Assume that the last element is the full path to the script or
+            # binary being run
+            return self.command[-1]
+        return None
+
+    def get_name(self):
+        return self.name
+
+
+class ExternalLibrary(Dependency):
+    # TODO: Add `language` support to all Dependency objects so that languages
+    # can be exposed for dependencies that support that (i.e., not pkg-config)
+    def __init__(self, name, link_args, language, silent=False):
+        super().__init__('external', {})
+        self.name = name
+        self.language = language
+        self.is_found = False
+        self.link_args = []
+        self.lang_args = []
+        if link_args:
+            self.is_found = True
+            if not isinstance(link_args, list):
+                link_args = [link_args]
+            self.lang_args = {language: link_args}
+            # We special-case Vala for now till the Dependency object gets
+            # proper support for exposing the language it was written in.
+            # Without this, vala-specific link args will end up in the C link
+            # args list if you link to a Vala library.
+            # This hack use to be in CompilerHolder.find_library().
+            if language != 'vala':
+                self.link_args = link_args
+        if not silent:
+            if self.is_found:
+                mlog.log('Library', mlog.bold(name), 'found:', mlog.green('YES'))
+            else:
+                mlog.log('Library', mlog.bold(name), 'found:', mlog.red('NO'))
+
+    def found(self):
+        return self.is_found
+
+    def get_name(self):
+        return self.name
+
+    def get_link_args(self):
+        return self.link_args
+
+    def get_lang_args(self, lang):
+        if lang in self.lang_args:
+            return self.lang_args[lang]
+        return []
+
+
+class ExtraFrameworkDependency(Dependency):
+    def __init__(self, name, required, path, kwargs):
+        Dependency.__init__(self, 'extraframeworks', kwargs)
+        self.name = None
+        self.detect(name, path)
+        if self.found():
+            mlog.log('Dependency', mlog.bold(name), 'found:', mlog.green('YES'),
+                     os.path.join(self.path, self.name))
+        else:
+            mlog.log('Dependency', name, 'found:', mlog.red('NO'))
+
+    def detect(self, name, path):
+        lname = name.lower()
+        if path is None:
+            paths = ['/Library/Frameworks']
+        else:
+            paths = [path]
+        for p in paths:
+            for d in os.listdir(p):
+                fullpath = os.path.join(p, d)
+                if lname != d.split('.')[0].lower():
+                    continue
+                if not stat.S_ISDIR(os.stat(fullpath).st_mode):
+                    continue
+                self.path = p
+                self.name = d
+                return
+
+    def get_compile_args(self):
+        if self.found():
+            return ['-I' + os.path.join(self.path, self.name, 'Headers')]
+        return []
+
+    def get_link_args(self):
+        if self.found():
+            return ['-F' + self.path, '-framework', self.name.split('.')[0]]
+        return []
+
+    def found(self):
+        return self.name is not None
+
+    def get_version(self):
+        return 'unknown'
+
+
+def get_dep_identifier(name, kwargs, want_cross):
+    # Need immutable objects since the identifier will be used as a dict key
+    version_reqs = flatten(kwargs.get('version', []))
+    if isinstance(version_reqs, list):
+        version_reqs = frozenset(version_reqs)
+    identifier = (name, version_reqs, want_cross)
+    for key, value in kwargs.items():
+        # 'version' is embedded above as the second element for easy access
+        # 'native' is handled above with `want_cross`
+        # 'required' is irrelevant for caching; the caller handles it separately
+        # 'fallback' subprojects cannot be cached -- they must be initialized
+        if key in ('version', 'native', 'required', 'fallback',):
+            continue
+        # All keyword arguments are strings, ints, or lists (or lists of lists)
+        if isinstance(value, list):
+            value = frozenset(flatten(value))
+        identifier += (key, value)
+    return identifier
+
+
+def find_external_dependency(name, environment, kwargs):
+    required = kwargs.get('required', True)
+    if not isinstance(required, bool):
+        raise DependencyException('Keyword "required" must be a boolean.')
+    if not isinstance(kwargs.get('method', ''), str):
+        raise DependencyException('Keyword "method" must be a string.')
+    lname = name.lower()
+    if lname in packages:
+        dep = packages[lname](environment, kwargs)
+        if required and not dep.found():
+            raise DependencyException('Dependency "%s" not found' % name)
+        return dep
+    pkg_exc = None
+    pkgdep = None
+    try:
+        pkgdep = PkgConfigDependency(name, environment, kwargs)
+        if pkgdep.found():
+            return pkgdep
+    except Exception as e:
+        pkg_exc = e
+    if mesonlib.is_osx():
+        fwdep = ExtraFrameworkDependency(name, required, None, kwargs)
+        if required and not fwdep.found():
+            m = 'Dependency {!r} not found, tried Extra Frameworks ' \
+                'and Pkg-Config:\n\n' + str(pkg_exc)
+            raise DependencyException(m.format(name))
+        return fwdep
+    if pkg_exc is not None:
+        raise pkg_exc
+    mlog.log('Dependency', mlog.bold(name), 'found:', mlog.red('NO'))
+    return pkgdep
diff --git a/mesonbuild/dependencies/dev.py b/mesonbuild/dependencies/dev.py
new file mode 100644
index 0000000..569108e
--- /dev/null
+++ b/mesonbuild/dependencies/dev.py
@@ -0,0 +1,293 @@
+# Copyright 2013-2017 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file contains the detection logic for external dependencies useful for
+# development purposes, such as testing, debugging, etc..
+
+import os
+import shlex
+import shutil
+
+from .. import mlog
+from .. import mesonlib
+from ..mesonlib import version_compare, Popen_safe
+from .base import Dependency, DependencyException, PkgConfigDependency
+
+
+class GTestDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'gtest', kwargs)
+        self.main = kwargs.get('main', False)
+        self.name = 'gtest'
+        self.libname = 'libgtest.so'
+        self.libmain_name = 'libgtest_main.so'
+        self.include_dir = '/usr/include'
+        self.src_dirs = ['/usr/src/gtest/src', '/usr/src/googletest/googletest/src']
+        self.detect()
+
+    def found(self):
+        return self.is_found
+
+    def detect(self):
+        trial_dirs = mesonlib.get_library_dirs()
+        glib_found = False
+        gmain_found = False
+        for d in trial_dirs:
+            if os.path.isfile(os.path.join(d, self.libname)):
+                glib_found = True
+            if os.path.isfile(os.path.join(d, self.libmain_name)):
+                gmain_found = True
+        if glib_found and gmain_found:
+            self.is_found = True
+            self.compile_args = []
+            self.link_args = ['-lgtest']
+            if self.main:
+                self.link_args.append('-lgtest_main')
+            self.sources = []
+            mlog.log('Dependency GTest found:', mlog.green('YES'), '(prebuilt)')
+        elif self.detect_srcdir():
+            self.is_found = True
+            self.compile_args = ['-I' + self.src_include_dir]
+            self.link_args = []
+            if self.main:
+                self.sources = [self.all_src, self.main_src]
+            else:
+                self.sources = [self.all_src]
+            mlog.log('Dependency GTest found:', mlog.green('YES'), '(building self)')
+        else:
+            mlog.log('Dependency GTest found:', mlog.red('NO'))
+            self.is_found = False
+        return self.is_found
+
+    def detect_srcdir(self):
+        for s in self.src_dirs:
+            if os.path.exists(s):
+                self.src_dir = s
+                self.all_src = mesonlib.File.from_absolute_file(
+                    os.path.join(self.src_dir, 'gtest-all.cc'))
+                self.main_src = mesonlib.File.from_absolute_file(
+                    os.path.join(self.src_dir, 'gtest_main.cc'))
+                self.src_include_dir = os.path.normpath(os.path.join(self.src_dir, '..'))
+                return True
+        return False
+
+    def get_compile_args(self):
+        arr = []
+        if self.include_dir != '/usr/include':
+            arr.append('-I' + self.include_dir)
+        if hasattr(self, 'src_include_dir'):
+            arr.append('-I' + self.src_include_dir)
+        return arr
+
+    def get_link_args(self):
+        return self.link_args
+
+    def get_version(self):
+        return '1.something_maybe'
+
+    def get_sources(self):
+        return self.sources
+
+    def need_threads(self):
+        return True
+
+
+class GMockDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'gmock', kwargs)
+        # GMock may be a library or just source.
+        # Work with both.
+        self.name = 'gmock'
+        self.libname = 'libgmock.so'
+        trial_dirs = mesonlib.get_library_dirs()
+        gmock_found = False
+        for d in trial_dirs:
+            if os.path.isfile(os.path.join(d, self.libname)):
+                gmock_found = True
+        if gmock_found:
+            self.is_found = True
+            self.compile_args = []
+            self.link_args = ['-lgmock']
+            self.sources = []
+            mlog.log('Dependency GMock found:', mlog.green('YES'), '(prebuilt)')
+            return
+
+        for d in ['/usr/src/googletest/googlemock/src', '/usr/src/gmock/src', '/usr/src/gmock']:
+            if os.path.exists(d):
+                self.is_found = True
+                # Yes, we need both because there are multiple
+                # versions of gmock that do different things.
+                d2 = os.path.normpath(os.path.join(d, '..'))
+                self.compile_args = ['-I' + d, '-I' + d2]
+                self.link_args = []
+                all_src = mesonlib.File.from_absolute_file(os.path.join(d, 'gmock-all.cc'))
+                main_src = mesonlib.File.from_absolute_file(os.path.join(d, 'gmock_main.cc'))
+                if kwargs.get('main', False):
+                    self.sources = [all_src, main_src]
+                else:
+                    self.sources = [all_src]
+                mlog.log('Dependency GMock found:', mlog.green('YES'), '(building self)')
+                return
+
+        mlog.log('Dependency GMock found:', mlog.red('NO'))
+        self.is_found = False
+
+    def get_version(self):
+        return '1.something_maybe'
+
+    def get_compile_args(self):
+        return self.compile_args
+
+    def get_sources(self):
+        return self.sources
+
+    def get_link_args(self):
+        return self.link_args
+
+    def found(self):
+        return self.is_found
+
+
+class LLVMDependency(Dependency):
+    """LLVM dependency.
+
+    LLVM uses a special tool, llvm-config, which has arguments for getting
+    c args, cxx args, and ldargs as well as version.
+    """
+
+    # Ordered list of llvm-config binaries to try. Start with base, then try
+    # newest back to oldest (3.5 is abitrary), and finally the devel version.
+    llvm_config_bins = [
+        'llvm-config', 'llvm-config-4.0', 'llvm-config-3.9', 'llvm-config39',
+        'llvm-config-3.8', 'llvm-config38', 'llvm-config-3.7', 'llvm-config37',
+        'llvm-config-3.6', 'llvm-config36', 'llvm-config-3.5', 'llvm-config35',
+        'llvm-config-devel',
+    ]
+    llvmconfig = None
+    _llvmconfig_found = False
+    __best_found = None
+    __cpp_blacklist = {'-DNDEBUG'}
+
+    def __init__(self, environment, kwargs):
+        super().__init__('llvm-config', kwargs)
+        # It's necessary for LLVM <= 3.8 to use the C++ linker. For 3.9 and 4.0
+        # the C linker works fine if only using the C API.
+        self.language = 'cpp'
+        self.cargs = []
+        self.libs = []
+        self.modules = []
+
+        required = kwargs.get('required', True)
+        req_version = kwargs.get('version', None)
+        if self.llvmconfig is None:
+            self.check_llvmconfig(req_version)
+        if not self._llvmconfig_found:
+            if self.__best_found is not None:
+                mlog.log('found {!r} but need:'.format(self.__best_found),
+                         req_version)
+            else:
+                mlog.log("No llvm-config found; can't detect dependency")
+            mlog.log('Dependency LLVM found:', mlog.red('NO'))
+            if required:
+                raise DependencyException('Dependency LLVM not found')
+            return
+
+        p, out, err = Popen_safe([self.llvmconfig, '--version'])
+        if p.returncode != 0:
+            mlog.debug('stdout: {}\nstderr: {}'.format(out, err))
+            if required:
+                raise DependencyException('Dependency LLVM not found')
+            return
+        else:
+            self.version = out.strip()
+            mlog.log('Dependency LLVM found:', mlog.green('YES'))
+            self.is_found = True
+
+            p, out = Popen_safe(
+                [self.llvmconfig, '--libs', '--ldflags', '--system-libs'])[:2]
+            if p.returncode != 0:
+                raise DependencyException('Could not generate libs for LLVM.')
+            self.libs = shlex.split(out)
+
+            p, out = Popen_safe([self.llvmconfig, '--cppflags'])[:2]
+            if p.returncode != 0:
+                raise DependencyException('Could not generate includedir for LLVM.')
+            self.cargs = list(mesonlib.OrderedSet(shlex.split(out)).difference(self.__cpp_blacklist))
+
+            p, out = Popen_safe([self.llvmconfig, '--components'])[:2]
+            if p.returncode != 0:
+                raise DependencyException('Could not generate modules for LLVM.')
+            self.modules = shlex.split(out)
+
+        modules = mesonlib.stringlistify(kwargs.get('modules', []))
+        for mod in modules:
+            if mod not in self.modules:
+                mlog.log('LLVM module', mod, 'found:', mlog.red('NO'))
+                self.is_found = False
+                if required:
+                    raise DependencyException(
+                        'Could not find required LLVM Component: {}'.format(mod))
+            else:
+                mlog.log('LLVM module', mod, 'found:', mlog.green('YES'))
+
+    def get_version(self):
+        return self.version
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.libs
+
+    @classmethod
+    def check_llvmconfig(cls, version_req):
+        """Try to find the highest version of llvm-config."""
+        for llvmconfig in cls.llvm_config_bins:
+            try:
+                p, out = Popen_safe([llvmconfig, '--version'])[0:2]
+                out = out.strip()
+                if p.returncode != 0:
+                    continue
+                if version_req:
+                    if version_compare(out, version_req, strict=True):
+                        if cls.__best_found and version_compare(out, '<={}'.format(cls.__best_found), strict=True):
+                            continue
+                        cls.__best_found = out
+                        cls.llvmconfig = llvmconfig
+                else:
+                    # If no specific version is requested use the first version
+                    # found, since that should be the best.
+                    cls.__best_found = out
+                    cls.llvmconfig = llvmconfig
+                    break
+            except (FileNotFoundError, PermissionError):
+                pass
+        if cls.__best_found:
+            mlog.log('Found llvm-config:',
+                     mlog.bold(shutil.which(cls.llvmconfig)),
+                     '({})'.format(out.strip()))
+            cls._llvmconfig_found = True
+        else:
+            cls.llvmconfig = False
+
+    def need_threads(self):
+        return True
+
+
+class ValgrindDependency(PkgConfigDependency):
+    def __init__(self, environment, kwargs):
+        PkgConfigDependency.__init__(self, 'valgrind', environment, kwargs)
+
+    def get_link_args(self):
+        return []
diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
new file mode 100644
index 0000000..3374c6e
--- /dev/null
+++ b/mesonbuild/dependencies/misc.py
@@ -0,0 +1,382 @@
+# Copyright 2013-2017 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file contains the detection logic for miscellaneous external dependencies.
+
+import glob
+import os
+import stat
+import sysconfig
+
+from .. import mlog
+from .. import mesonlib
+from ..environment import detect_cpu_family
+
+from .base import Dependency, DependencyException, DependencyMethods, ExtraFrameworkDependency, PkgConfigDependency
+
+
+class BoostDependency(Dependency):
+    # Some boost libraries have different names for
+    # their sources and libraries. This dict maps
+    # between the two.
+    name2lib = {'test': 'unit_test_framework'}
+
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'boost', kwargs)
+        self.name = 'boost'
+        self.environment = environment
+        self.libdir = ''
+        if 'native' in kwargs and environment.is_cross_build():
+            self.want_cross = not kwargs['native']
+        else:
+            self.want_cross = environment.is_cross_build()
+        try:
+            self.boost_root = os.environ['BOOST_ROOT']
+            if not os.path.isabs(self.boost_root):
+                raise DependencyException('BOOST_ROOT must be an absolute path.')
+        except KeyError:
+            self.boost_root = None
+        if self.boost_root is None:
+            if self.want_cross:
+                if 'BOOST_INCLUDEDIR' in os.environ:
+                    self.incdir = os.environ['BOOST_INCLUDEDIR']
+                else:
+                    raise DependencyException('BOOST_ROOT or BOOST_INCLUDEDIR is needed while cross-compiling')
+            if mesonlib.is_windows():
+                self.boost_root = self.detect_win_root()
+                self.incdir = self.boost_root
+            else:
+                if 'BOOST_INCLUDEDIR' in os.environ:
+                    self.incdir = os.environ['BOOST_INCLUDEDIR']
+                else:
+                    self.incdir = '/usr/include'
+        else:
+            self.incdir = os.path.join(self.boost_root, 'include')
+        self.boost_inc_subdir = os.path.join(self.incdir, 'boost')
+        mlog.debug('Boost library root dir is', self.boost_root)
+        self.src_modules = {}
+        self.lib_modules = {}
+        self.lib_modules_mt = {}
+        self.detect_version()
+        self.requested_modules = self.get_requested(kwargs)
+        module_str = ', '.join(self.requested_modules)
+        if self.version is not None:
+            self.detect_src_modules()
+            self.detect_lib_modules()
+            self.validate_requested()
+            if self.boost_root is not None:
+                info = self.version + ', ' + self.boost_root
+            else:
+                info = self.version
+            mlog.log('Dependency Boost (%s) found:' % module_str, mlog.green('YES'), info)
+        else:
+            mlog.log("Dependency Boost (%s) found:" % module_str, mlog.red('NO'))
+        if 'cpp' not in self.environment.coredata.compilers:
+            raise DependencyException('Tried to use Boost but a C++ compiler is not defined.')
+        self.cpp_compiler = self.environment.coredata.compilers['cpp']
+
+    def detect_win_root(self):
+        globtext = 'c:\\local\\boost_*'
+        files = glob.glob(globtext)
+        if len(files) > 0:
+            return files[0]
+        return 'C:\\'
+
+    def get_compile_args(self):
+        args = []
+        include_dir = ''
+        if self.boost_root is not None:
+            if mesonlib.is_windows():
+                include_dir = self.boost_root
+            else:
+                include_dir = os.path.join(self.boost_root, 'include')
+        else:
+            include_dir = self.incdir
+
+        # Use "-isystem" when including boost headers instead of "-I"
+        # to avoid compiler warnings/failures when "-Werror" is used
+
+        # Careful not to use "-isystem" on default include dirs as it
+        # breaks some of the headers for certain gcc versions
+
+        # For example, doing g++ -isystem /usr/include on a simple
+        # "int main()" source results in the error:
+        # "/usr/include/c++/6.3.1/cstdlib:75:25: fatal error: stdlib.h: No such file or directory"
+
+        # See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129
+        # and http://stackoverflow.com/questions/37218953/isystem-on-a-system-include-directory-causes-errors
+        # for more details
+
+        # TODO: The correct solution would probably be to ask the
+        # compiler for it's default include paths (ie: "gcc -xc++ -E
+        # -v -") and avoid including those with -isystem
+
+        # For now, use -isystem for all includes except for some
+        # typical defaults (which don't need to be included at all
+        # since they are in the default include paths)
+        if include_dir != '/usr/include' and include_dir != '/usr/local/include':
+            args.append("".join(self.cpp_compiler.get_include_args(include_dir, True)))
+        return args
+
+    def get_requested(self, kwargs):
+        candidates = kwargs.get('modules', [])
+        if isinstance(candidates, str):
+            return [candidates]
+        for c in candidates:
+            if not isinstance(c, str):
+                raise DependencyException('Boost module argument is not a string.')
+        return candidates
+
+    def validate_requested(self):
+        for m in self.requested_modules:
+            if m not in self.src_modules:
+                raise DependencyException('Requested Boost module "%s" not found.' % m)
+
+    def found(self):
+        return self.version is not None
+
+    def get_version(self):
+        return self.version
+
+    def detect_version(self):
+        try:
+            ifile = open(os.path.join(self.boost_inc_subdir, 'version.hpp'))
+        except FileNotFoundError:
+            self.version = None
+            return
+        with ifile:
+            for line in ifile:
+                if line.startswith("#define") and 'BOOST_LIB_VERSION' in line:
+                    ver = line.split()[-1]
+                    ver = ver[1:-1]
+                    self.version = ver.replace('_', '.')
+                    return
+        self.version = None
+
+    def detect_src_modules(self):
+        for entry in os.listdir(self.boost_inc_subdir):
+            entry = os.path.join(self.boost_inc_subdir, entry)
+            if stat.S_ISDIR(os.stat(entry).st_mode):
+                self.src_modules[os.path.split(entry)[-1]] = True
+
+    def detect_lib_modules(self):
+        if mesonlib.is_windows():
+            return self.detect_lib_modules_win()
+        return self.detect_lib_modules_nix()
+
+    def detect_lib_modules_win(self):
+        arch = detect_cpu_family(self.environment.coredata.compilers)
+        # Guess the libdir
+        if arch == 'x86':
+            gl = 'lib32*'
+        elif arch == 'x86_64':
+            gl = 'lib64*'
+        else:
+            # Does anyone do Boost cross-compiling to other archs on Windows?
+            gl = None
+        # See if the libdir is valid
+        if gl:
+            libdir = glob.glob(os.path.join(self.boost_root, gl))
+        else:
+            libdir = []
+        # Can't find libdir, bail
+        if not libdir:
+            return
+        libdir = libdir[0]
+        self.libdir = libdir
+        globber = 'boost_*-gd-*.lib'  # FIXME
+        for entry in glob.glob(os.path.join(libdir, globber)):
+            (_, fname) = os.path.split(entry)
+            base = fname.split('_', 1)[1]
+            modname = base.split('-', 1)[0]
+            self.lib_modules_mt[modname] = fname
+
+    def detect_lib_modules_nix(self):
+        if mesonlib.is_osx():
+            libsuffix = 'dylib'
+        else:
+            libsuffix = 'so'
+
+        globber = 'libboost_*.{}'.format(libsuffix)
+        if 'BOOST_LIBRARYDIR' in os.environ:
+            libdirs = [os.environ['BOOST_LIBRARYDIR']]
+        elif self.boost_root is None:
+            libdirs = mesonlib.get_library_dirs()
+        else:
+            libdirs = [os.path.join(self.boost_root, 'lib')]
+        for libdir in libdirs:
+            for entry in glob.glob(os.path.join(libdir, globber)):
+                lib = os.path.basename(entry)
+                name = lib.split('.')[0].split('_', 1)[-1]
+                # I'm not 100% sure what to do here. Some distros
+                # have modules such as thread only as -mt versions.
+                if entry.endswith('-mt.so'):
+                    self.lib_modules_mt[name] = True
+                else:
+                    self.lib_modules[name] = True
+
+    def get_win_link_args(self):
+        args = []
+        if self.boost_root:
+            args.append('-L' + self.libdir)
+        for module in self.requested_modules:
+            module = BoostDependency.name2lib.get(module, module)
+            if module in self.lib_modules_mt:
+                args.append(self.lib_modules_mt[module])
+        return args
+
+    def get_link_args(self):
+        if mesonlib.is_windows():
+            return self.get_win_link_args()
+        args = []
+        if self.boost_root:
+            args.append('-L' + os.path.join(self.boost_root, 'lib'))
+        elif 'BOOST_LIBRARYDIR' in os.environ:
+            args.append('-L' + os.environ['BOOST_LIBRARYDIR'])
+        for module in self.requested_modules:
+            module = BoostDependency.name2lib.get(module, module)
+            libname = 'boost_' + module
+            # The compiler's library detector is the most reliable so use that first.
+            default_detect = self.cpp_compiler.find_library(libname, self.environment, [])
+            if default_detect is not None:
+                if module == 'unit_testing_framework':
+                    emon_args = self.cpp_compiler.find_library('boost_test_exec_monitor')
+                else:
+                    emon_args = None
+                args += default_detect
+                if emon_args is not None:
+                    args += emon_args
+            elif module in self.lib_modules or module in self.lib_modules_mt:
+                linkcmd = '-l' + libname
+                args.append(linkcmd)
+                # FIXME a hack, but Boost's testing framework has a lot of
+                # different options and it's hard to determine what to do
+                # without feedback from actual users. Update this
+                # as we get more bug reports.
+                if module == 'unit_testing_framework':
+                    args.append('-lboost_test_exec_monitor')
+            elif module + '-mt' in self.lib_modules_mt:
+                linkcmd = '-lboost_' + module + '-mt'
+                args.append(linkcmd)
+                if module == 'unit_testing_framework':
+                    args.append('-lboost_test_exec_monitor-mt')
+        return args
+
+    def get_sources(self):
+        return []
+
+    def need_threads(self):
+        return 'thread' in self.requested_modules
+
+
+class ThreadDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        super().__init__('threads', {})
+        self.name = 'threads'
+        self.is_found = True
+        mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
+
+    def need_threads(self):
+        return True
+
+    def get_version(self):
+        return 'unknown'
+
+
+class Python3Dependency(Dependency):
+    def __init__(self, environment, kwargs):
+        super().__init__('python3', kwargs)
+        self.name = 'python3'
+        self.is_found = False
+        # We can only be sure that it is Python 3 at this point
+        self.version = '3'
+        if DependencyMethods.PKGCONFIG in self.methods:
+            try:
+                pkgdep = PkgConfigDependency('python3', environment, kwargs)
+                if pkgdep.found():
+                    self.cargs = pkgdep.cargs
+                    self.libs = pkgdep.libs
+                    self.version = pkgdep.get_version()
+                    self.is_found = True
+                    return
+            except Exception:
+                pass
+        if not self.is_found:
+            if mesonlib.is_windows() and DependencyMethods.SYSCONFIG in self.methods:
+                self._find_libpy3_windows(environment)
+            elif mesonlib.is_osx() and DependencyMethods.EXTRAFRAMEWORK in self.methods:
+                # In OSX the Python 3 framework does not have a version
+                # number in its name.
+                fw = ExtraFrameworkDependency('python', False, None, kwargs)
+                if fw.found():
+                    self.cargs = fw.get_compile_args()
+                    self.libs = fw.get_link_args()
+                    self.is_found = True
+        if self.is_found:
+            mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
+        else:
+            mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.red('NO'))
+
+    def _find_libpy3_windows(self, env):
+        '''
+        Find python3 libraries on Windows and also verify that the arch matches
+        what we are building for.
+        '''
+        pyarch = sysconfig.get_platform()
+        arch = detect_cpu_family(env.coredata.compilers)
+        if arch == 'x86':
+            arch = '32'
+        elif arch == 'x86_64':
+            arch = '64'
+        else:
+            # We can't cross-compile Python 3 dependencies on Windows yet
+            mlog.log('Unknown architecture {!r} for'.format(arch),
+                     mlog.bold(self.name))
+            self.is_found = False
+            return
+        # Pyarch ends in '32' or '64'
+        if arch != pyarch[-2:]:
+            mlog.log('Need', mlog.bold(self.name),
+                     'for {}-bit, but found {}-bit'.format(arch, pyarch[-2:]))
+            self.is_found = False
+            return
+        inc = sysconfig.get_path('include')
+        platinc = sysconfig.get_path('platinclude')
+        self.cargs = ['-I' + inc]
+        if inc != platinc:
+            self.cargs.append('-I' + platinc)
+        # Nothing exposes this directly that I coulf find
+        basedir = sysconfig.get_config_var('base')
+        vernum = sysconfig.get_config_var('py_version_nodot')
+        self.libs = ['-L{}/libs'.format(basedir),
+                     '-lpython{}'.format(vernum)]
+        self.version = sysconfig.get_config_var('py_version_short')
+        self.is_found = True
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.libs
+
+    def get_methods(self):
+        if mesonlib.is_windows():
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSCONFIG]
+        elif mesonlib.is_osx():
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.EXTRAFRAMEWORK]
+        else:
+            return [DependencyMethods.PKGCONFIG]
+
+    def get_version(self):
+        return self.version
diff --git a/mesonbuild/dependencies/platform.py b/mesonbuild/dependencies/platform.py
new file mode 100644
index 0000000..cd46412
--- /dev/null
+++ b/mesonbuild/dependencies/platform.py
@@ -0,0 +1,44 @@
+# Copyright 2013-2017 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file contains the detection logic for external dependencies that are
+# platform-specific (generally speaking).
+
+from .. import mesonlib
+
+from .base import Dependency, DependencyException
+
+
+class AppleFrameworks(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'appleframeworks', kwargs)
+        modules = kwargs.get('modules', [])
+        if isinstance(modules, str):
+            modules = [modules]
+        if not modules:
+            raise DependencyException("AppleFrameworks dependency requires at least one module.")
+        self.frameworks = modules
+
+    def get_link_args(self):
+        args = []
+        for f in self.frameworks:
+            args.append('-framework')
+            args.append(f)
+        return args
+
+    def found(self):
+        return mesonlib.is_osx()
+
+    def get_version(self):
+        return 'unknown'
diff --git a/mesonbuild/dependencies/ui.py b/mesonbuild/dependencies/ui.py
new file mode 100644
index 0000000..3174176
--- /dev/null
+++ b/mesonbuild/dependencies/ui.py
@@ -0,0 +1,560 @@
+# Copyright 2013-2017 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file contains the detection logic for external dependencies that
+# are UI-related.
+
+import os
+import re
+import shutil
+import subprocess
+from collections import OrderedDict
+
+from .. import mlog
+from .. import mesonlib
+from ..mesonlib import MesonException, Popen_safe, version_compare
+from ..environment import for_windows
+
+from .base import (Dependency, DependencyException, DependencyMethods,
+                   ExternalProgram, ExtraFrameworkDependency, PkgConfigDependency)
+
+
+class GLDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'gl', kwargs)
+        self.is_found = False
+        self.cargs = []
+        self.linkargs = []
+        if DependencyMethods.PKGCONFIG in self.methods:
+            try:
+                pcdep = PkgConfigDependency('gl', environment, kwargs)
+                if pcdep.found():
+                    self.type_name = 'pkgconfig'
+                    self.is_found = True
+                    self.cargs = pcdep.get_compile_args()
+                    self.linkargs = pcdep.get_link_args()
+                    self.version = pcdep.get_version()
+                    return
+            except Exception:
+                pass
+        if DependencyMethods.SYSTEM in self.methods:
+            if mesonlib.is_osx():
+                self.is_found = True
+                self.linkargs = ['-framework', 'OpenGL']
+                self.version = '1'  # FIXME
+                return
+            if mesonlib.is_windows():
+                self.is_found = True
+                self.linkargs = ['-lopengl32']
+                self.version = '1'  # FIXME: unfixable?
+                return
+
+    def get_link_args(self):
+        return self.linkargs
+
+    def get_version(self):
+        return self.version
+
+    def get_methods(self):
+        if mesonlib.is_osx() or mesonlib.is_windows():
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM]
+        else:
+            return [DependencyMethods.PKGCONFIG]
+
+
+class GnuStepDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'gnustep', kwargs)
+        self.required = kwargs.get('required', True)
+        self.modules = kwargs.get('modules', [])
+        self.detect()
+
+    def detect(self):
+        self.confprog = 'gnustep-config'
+        try:
+            gp = Popen_safe([self.confprog, '--help'])[0]
+        except (FileNotFoundError, PermissionError):
+            self.args = None
+            mlog.log('Dependency GnuStep found:', mlog.red('NO'), '(no gnustep-config)')
+            return
+        if gp.returncode != 0:
+            self.args = None
+            mlog.log('Dependency GnuStep found:', mlog.red('NO'))
+            return
+        if 'gui' in self.modules:
+            arg = '--gui-libs'
+        else:
+            arg = '--base-libs'
+        fp, flagtxt, flagerr = Popen_safe([self.confprog, '--objc-flags'])
+        if fp.returncode != 0:
+            raise DependencyException('Error getting objc-args: %s %s' % (flagtxt, flagerr))
+        args = flagtxt.split()
+        self.args = self.filter_arsg(args)
+        fp, libtxt, liberr = Popen_safe([self.confprog, arg])
+        if fp.returncode != 0:
+            raise DependencyException('Error getting objc-lib args: %s %s' % (libtxt, liberr))
+        self.libs = self.weird_filter(libtxt.split())
+        self.version = self.detect_version()
+        mlog.log('Dependency', mlog.bold('GnuStep'), 'found:',
+                 mlog.green('YES'), self.version)
+
+    def weird_filter(self, elems):
+        """When building packages, the output of the enclosing Make
+is sometimes mixed among the subprocess output. I have no idea
+why. As a hack filter out everything that is not a flag."""
+        return [e for e in elems if e.startswith('-')]
+
+    def filter_arsg(self, args):
+        """gnustep-config returns a bunch of garbage args such
+        as -O2 and so on. Drop everything that is not needed."""
+        result = []
+        for f in args:
+            if f.startswith('-D') \
+                    or f.startswith('-f') \
+                    or f.startswith('-I') \
+                    or f == '-pthread' \
+                    or (f.startswith('-W') and not f == '-Wall'):
+                result.append(f)
+        return result
+
+    def detect_version(self):
+        gmake = self.get_variable('GNUMAKE')
+        makefile_dir = self.get_variable('GNUSTEP_MAKEFILES')
+        # This Makefile has the GNUStep version set
+        base_make = os.path.join(makefile_dir, 'Additional', 'base.make')
+        # Print the Makefile variable passed as the argument. For instance, if
+        # you run the make target `print-SOME_VARIABLE`, this will print the
+        # value of the variable `SOME_VARIABLE`.
+        printver = "print-%:\n\t@echo '$($*)'"
+        env = os.environ.copy()
+        # See base.make to understand why this is set
+        env['FOUNDATION_LIB'] = 'gnu'
+        p, o, e = Popen_safe([gmake, '-f', '-', '-f', base_make,
+                              'print-GNUSTEP_BASE_VERSION'],
+                             env=env, write=printver, stdin=subprocess.PIPE)
+        version = o.strip()
+        if not version:
+            mlog.debug("Couldn't detect GNUStep version, falling back to '1'")
+            # Fallback to setting some 1.x version
+            version = '1'
+        return version
+
+    def get_variable(self, var):
+        p, o, e = Popen_safe([self.confprog, '--variable=' + var])
+        if p.returncode != 0 and self.required:
+            raise DependencyException('{!r} for variable {!r} failed to run'
+                                      ''.format(self.confprog, var))
+        return o.strip()
+
+    def found(self):
+        return self.args is not None
+
+    def get_version(self):
+        return self.version
+
+    def get_compile_args(self):
+        if self.args is None:
+            return []
+        return self.args
+
+    def get_link_args(self):
+        return self.libs
+
+
+class QtBaseDependency(Dependency):
+    def __init__(self, name, env, kwargs):
+        Dependency.__init__(self, name, kwargs)
+        self.name = name
+        self.qtname = name.capitalize()
+        self.qtver = name[-1]
+        if self.qtver == "4":
+            self.qtpkgname = 'Qt'
+        else:
+            self.qtpkgname = self.qtname
+        self.root = '/usr'
+        self.bindir = None
+        self.silent = kwargs.get('silent', False)
+        # We store the value of required here instead of passing it on to
+        # PkgConfigDependency etc because we want to try the qmake-based
+        # fallback as well.
+        self.required = kwargs.pop('required', True)
+        kwargs['required'] = False
+        mods = kwargs.get('modules', [])
+        self.cargs = []
+        self.largs = []
+        self.is_found = False
+        if isinstance(mods, str):
+            mods = [mods]
+        if not mods:
+            raise DependencyException('No ' + self.qtname + '  modules specified.')
+        type_text = 'cross' if env.is_cross_build() else 'native'
+        found_msg = '{} {} {{}} dependency (modules: {}) found:' \
+                    ''.format(self.qtname, type_text, ', '.join(mods))
+        from_text = 'pkg-config'
+
+        # Keep track of the detection methods used, for logging purposes.
+        methods = []
+        # Prefer pkg-config, then fallback to `qmake -query`
+        if DependencyMethods.PKGCONFIG in self.methods:
+            self._pkgconfig_detect(mods, env, kwargs)
+            methods.append('pkgconfig')
+        if not self.is_found and DependencyMethods.QMAKE in self.methods:
+            from_text = self._qmake_detect(mods, env, kwargs)
+            methods.append('qmake-' + self.name)
+            methods.append('qmake')
+        if not self.is_found:
+            # Reset compile args and link args
+            self.cargs = []
+            self.largs = []
+            from_text = '(checked {})'.format(mlog.format_list(methods))
+            self.version = 'none'
+            if self.required:
+                err_msg = '{} {} dependency not found {}' \
+                          ''.format(self.qtname, type_text, from_text)
+                raise DependencyException(err_msg)
+            if not self.silent:
+                mlog.log(found_msg.format(from_text), mlog.red('NO'))
+            return
+        from_text = '`{}`'.format(from_text)
+        if not self.silent:
+            mlog.log(found_msg.format(from_text), mlog.green('YES'))
+
+    def compilers_detect(self):
+        "Detect Qt (4 or 5) moc, uic, rcc in the specified bindir or in PATH"
+        if self.bindir:
+            moc = ExternalProgram(os.path.join(self.bindir, 'moc'), silent=True)
+            uic = ExternalProgram(os.path.join(self.bindir, 'uic'), silent=True)
+            rcc = ExternalProgram(os.path.join(self.bindir, 'rcc'), silent=True)
+        else:
+            # We don't accept unsuffixed 'moc', 'uic', and 'rcc' because they
+            # are sometimes older, or newer versions.
+            moc = ExternalProgram('moc-' + self.name, silent=True)
+            uic = ExternalProgram('uic-' + self.name, silent=True)
+            rcc = ExternalProgram('rcc-' + self.name, silent=True)
+        return moc, uic, rcc
+
+    def _pkgconfig_detect(self, mods, env, kwargs):
+        modules = OrderedDict()
+        for module in mods:
+            modules[module] = PkgConfigDependency(self.qtpkgname + module, env, kwargs)
+        self.is_found = True
+        for m in modules.values():
+            if not m.found():
+                self.is_found = False
+                return
+            self.cargs += m.get_compile_args()
+            self.largs += m.get_link_args()
+        self.version = m.modversion
+        # Try to detect moc, uic, rcc
+        if 'Core' in modules:
+            core = modules['Core']
+        else:
+            corekwargs = {'required': 'false', 'silent': 'true'}
+            core = PkgConfigDependency(self.qtpkgname + 'Core', env, corekwargs)
+        # Used by self.compilers_detect()
+        self.bindir = self.get_pkgconfig_host_bins(core)
+        if not self.bindir:
+            # If exec_prefix is not defined, the pkg-config file is broken
+            prefix = core.get_pkgconfig_variable('exec_prefix')
+            if prefix:
+                self.bindir = os.path.join(prefix, 'bin')
+
+    def _find_qmake(self, qmake, env):
+        # Even when cross-compiling, if we don't get a cross-info qmake, we
+        # fallback to using the qmake in PATH because that's what we used to do
+        if env.is_cross_build():
+            qmake = env.cross_info.config['binaries'].get('qmake', qmake)
+        return ExternalProgram(qmake, silent=True)
+
+    def _qmake_detect(self, mods, env, kwargs):
+        for qmake in ('qmake-' + self.name, 'qmake'):
+            self.qmake = self._find_qmake(qmake, env)
+            if not self.qmake.found():
+                continue
+            # Check that the qmake is for qt5
+            pc, stdo = Popen_safe(self.qmake.get_command() + ['-v'])[0:2]
+            if pc.returncode != 0:
+                continue
+            if not 'Qt version ' + self.qtver in stdo:
+                mlog.log('QMake is not for ' + self.qtname)
+                continue
+            # Found qmake for Qt5!
+            break
+        else:
+            # Didn't find qmake :(
+            return
+        self.version = re.search(self.qtver + '(\.\d+)+', stdo).group(0)
+        # Query library path, header path, and binary path
+        mlog.log("Found qmake:", mlog.bold(self.qmake.get_name()), '(%s)' % self.version)
+        stdo = Popen_safe(self.qmake.get_command() + ['-query'])[1]
+        qvars = {}
+        for line in stdo.split('\n'):
+            line = line.strip()
+            if line == '':
+                continue
+            (k, v) = tuple(line.split(':', 1))
+            qvars[k] = v
+        if mesonlib.is_osx():
+            return self._framework_detect(qvars, mods, kwargs)
+        incdir = qvars['QT_INSTALL_HEADERS']
+        self.cargs.append('-I' + incdir)
+        libdir = qvars['QT_INSTALL_LIBS']
+        # Used by self.compilers_detect()
+        self.bindir = self.get_qmake_host_bins(qvars)
+        self.is_found = True
+        for module in mods:
+            mincdir = os.path.join(incdir, 'Qt' + module)
+            self.cargs.append('-I' + mincdir)
+            if for_windows(env.is_cross_build(), env):
+                libfile = os.path.join(libdir, self.qtpkgname + module + '.lib')
+                if not os.path.isfile(libfile):
+                    # MinGW can link directly to .dll
+                    libfile = os.path.join(self.bindir, self.qtpkgname + module + '.dll')
+                    if not os.path.isfile(libfile):
+                        self.is_found = False
+                        break
+            else:
+                libfile = os.path.join(libdir, 'lib{}{}.so'.format(self.qtpkgname, module))
+                if not os.path.isfile(libfile):
+                    self.is_found = False
+                    break
+            self.largs.append(libfile)
+        return qmake
+
+    def _framework_detect(self, qvars, modules, kwargs):
+        libdir = qvars['QT_INSTALL_LIBS']
+        for m in modules:
+            fname = 'Qt' + m
+            fwdep = ExtraFrameworkDependency(fname, kwargs.get('required', True), libdir, kwargs)
+            self.cargs.append('-F' + libdir)
+            if fwdep.found():
+                self.is_found = True
+                self.cargs += fwdep.get_compile_args()
+                self.largs += fwdep.get_link_args()
+        # Used by self.compilers_detect()
+        self.bindir = self.get_qmake_host_bins(qvars)
+
+    def get_qmake_host_bins(self, qvars):
+        # Prefer QT_HOST_BINS (qt5, correct for cross and native compiling)
+        # but fall back to QT_INSTALL_BINS (qt4)
+        if 'QT_HOST_BINS' in qvars:
+            return qvars['QT_HOST_BINS']
+        else:
+            return qvars['QT_INSTALL_BINS']
+
+    def get_version(self):
+        return self.version
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_sources(self):
+        return []
+
+    def get_link_args(self):
+        return self.largs
+
+    def get_methods(self):
+        return [DependencyMethods.PKGCONFIG, DependencyMethods.QMAKE]
+
+    def found(self):
+        return self.is_found
+
+    def get_exe_args(self, compiler):
+        # Originally this was -fPIE but nowadays the default
+        # for upstream and distros seems to be -reduce-relocations
+        # which requires -fPIC. This may cause a performance
+        # penalty when using self-built Qt or on platforms
+        # where -fPIC is not required. If this is an issue
+        # for you, patches are welcome.
+        return compiler.get_pic_args()
+
+
+class Qt4Dependency(QtBaseDependency):
+    def __init__(self, env, kwargs):
+        QtBaseDependency.__init__(self, 'qt4', env, kwargs)
+
+    def get_pkgconfig_host_bins(self, core):
+        # Only return one bins dir, because the tools are generally all in one
+        # directory for Qt4, in Qt5, they must all be in one directory. Return
+        # the first one found among the bin variables, in case one tool is not
+        # configured to be built.
+        applications = ['moc', 'uic', 'rcc', 'lupdate', 'lrelease']
+        for application in applications:
+            try:
+                return os.path.dirname(core.get_pkgconfig_variable('%s_location' % application))
+            except MesonException:
+                pass
+
+
+class Qt5Dependency(QtBaseDependency):
+    def __init__(self, env, kwargs):
+        QtBaseDependency.__init__(self, 'qt5', env, kwargs)
+
+    def get_pkgconfig_host_bins(self, core):
+        return core.get_pkgconfig_variable('host_bins')
+
+
+# There are three different ways of depending on SDL2:
+# sdl2-config, pkg-config and OSX framework
+class SDL2Dependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'sdl2', kwargs)
+        self.is_found = False
+        self.cargs = []
+        self.linkargs = []
+        if DependencyMethods.PKGCONFIG in self.methods:
+            try:
+                pcdep = PkgConfigDependency('sdl2', environment, kwargs)
+                if pcdep.found():
+                    self.type_name = 'pkgconfig'
+                    self.is_found = True
+                    self.cargs = pcdep.get_compile_args()
+                    self.linkargs = pcdep.get_link_args()
+                    self.version = pcdep.get_version()
+                    return
+            except Exception as e:
+                mlog.debug('SDL 2 not found via pkgconfig. Trying next, error was:', str(e))
+                pass
+        if DependencyMethods.SDLCONFIG in self.methods:
+            sdlconf = shutil.which('sdl2-config')
+            if sdlconf:
+                stdo = Popen_safe(['sdl2-config', '--cflags'])[1]
+                self.cargs = stdo.strip().split()
+                stdo = Popen_safe(['sdl2-config', '--libs'])[1]
+                self.linkargs = stdo.strip().split()
+                stdo = Popen_safe(['sdl2-config', '--version'])[1]
+                self.version = stdo.strip()
+                self.is_found = True
+                mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.green('YES'),
+                         self.version, '(%s)' % sdlconf)
+                return
+            mlog.debug('Could not find sdl2-config binary, trying next.')
+        if DependencyMethods.EXTRAFRAMEWORK in self.methods:
+            if mesonlib.is_osx():
+                fwdep = ExtraFrameworkDependency('sdl2', kwargs.get('required', True), None, kwargs)
+                if fwdep.found():
+                    self.is_found = True
+                    self.cargs = fwdep.get_compile_args()
+                    self.linkargs = fwdep.get_link_args()
+                    self.version = '2'  # FIXME
+                    return
+            mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.red('NO'))
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.linkargs
+
+    def found(self):
+        return self.is_found
+
+    def get_version(self):
+        return self.version
+
+    def get_methods(self):
+        if mesonlib.is_osx():
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG, DependencyMethods.EXTRAFRAMEWORK]
+        else:
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG]
+
+
+class WxDependency(Dependency):
+    wx_found = None
+
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'wx', kwargs)
+        self.is_found = False
+        # FIXME: use version instead of modversion
+        self.modversion = 'none'
+        if WxDependency.wx_found is None:
+            self.check_wxconfig()
+        if not WxDependency.wx_found:
+            # FIXME: this message could be printed after Dependncy found
+            mlog.log("Neither wx-config-3.0 nor wx-config found; can't detect dependency")
+            return
+
+        # FIXME: This should print stdout and stderr using mlog.debug
+        p, out = Popen_safe([self.wxc, '--version'])[0:2]
+        if p.returncode != 0:
+            mlog.log('Dependency wxwidgets found:', mlog.red('NO'))
+            self.cargs = []
+            self.libs = []
+        else:
+            self.modversion = out.strip()
+            version_req = kwargs.get('version', None)
+            if version_req is not None:
+                if not version_compare(self.modversion, version_req, strict=True):
+                    mlog.log('Wxwidgets version %s does not fullfill requirement %s' %
+                             (self.modversion, version_req))
+                    return
+            mlog.log('Dependency wxwidgets found:', mlog.green('YES'))
+            self.is_found = True
+            self.requested_modules = self.get_requested(kwargs)
+            # wx-config seems to have a cflags as well but since it requires C++,
+            # this should be good, at least for now.
+            p, out = Popen_safe([self.wxc, '--cxxflags'])[0:2]
+            # FIXME: this error should only be raised if required is true
+            if p.returncode != 0:
+                raise DependencyException('Could not generate cargs for wxwidgets.')
+            self.cargs = out.split()
+
+            # FIXME: this error should only be raised if required is true
+            p, out = Popen_safe([self.wxc, '--libs'] + self.requested_modules)[0:2]
+            if p.returncode != 0:
+                raise DependencyException('Could not generate libs for wxwidgets.')
+            self.libs = out.split()
+
+    def get_requested(self, kwargs):
+        modules = 'modules'
+        if modules not in kwargs:
+            return []
+        candidates = kwargs[modules]
+        if isinstance(candidates, str):
+            return [candidates]
+        for c in candidates:
+            if not isinstance(c, str):
+                raise DependencyException('wxwidgets module argument is not a string.')
+        return candidates
+
+    def get_modversion(self):
+        return self.modversion
+
+    def get_version(self):
+        return self.modversion
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.libs
+
+    def check_wxconfig(self):
+        for wxc in ['wx-config-3.0', 'wx-config']:
+            try:
+                p, out = Popen_safe([wxc, '--version'])[0:2]
+                if p.returncode == 0:
+                    mlog.log('Found wx-config:', mlog.bold(shutil.which(wxc)),
+                             '(%s)' % out.strip())
+                    self.wxc = wxc
+                    WxDependency.wx_found = True
+                    return
+            except (FileNotFoundError, PermissionError):
+                pass
+        WxDependency.wxconfig_found = False
+        mlog.log('Found wx-config:', mlog.red('NO'))
+
+    def found(self):
+        return self.is_found