intl custom dependency

Checking how to aquire the *gettext family of symbols portably is
annoyingly complex, and may come from the libc, or standalone.

builtin dependency:

    This detects if libintl is unneeded, because the *gettext family of
    symbols is available in the libc.

system dependency:

    This detects if libintl is installed as separate software, linkable via
    -lintl; unfortunately, GNU gettext does not ship pkg-config files for
    it.

Fixes #3929

2 files changed, 29 insertions, 2 deletions

diff --git a/mesonbuild/dependencies/__init__.py b/mesonbuild/dependencies/__init__.py
index 0dafae1..bd90c90 100644
--- a/mesonbuild/dependencies/__init__.py
+++ b/mesonbuild/dependencies/__init__.py
@@ -35,7 +35,7 @@ from .scalapack import scalapack_factory
 from .misc import (
     BlocksDependency, OpenMPDependency, cups_factory, curses_factory, gpgme_factory,
     libgcrypt_factory, libwmf_factory, netcdf_factory, pcap_factory, python3_factory,
-    shaderc_factory, threads_factory, ThreadDependency,
+    shaderc_factory, threads_factory, ThreadDependency, intl_factory,
 )
 from .platform import AppleFrameworks
 from .qt import qt4_factory, qt5_factory, qt6_factory
@@ -252,6 +252,7 @@ packages.update({
     'libgcrypt': libgcrypt_factory,
     'gpgme': gpgme_factory,
     'shaderc': shaderc_factory,
+    'intl': intl_factory,
 
     # From platform:
     'appleframeworks': AppleFrameworks,
diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index 87b1a9b..f131cb7 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -24,7 +24,7 @@ from .. import mesonlib
 from .. import mlog
 from ..environment import detect_cpu_family
 from .base import DependencyException, DependencyMethods
-from .base import SystemDependency
+from .base import BuiltinDependency, SystemDependency
 from .cmake import CMakeDependency
 from .configtool import ConfigToolDependency
 from .factory import DependencyFactory, factory_methods
@@ -487,6 +487,25 @@ class CursesSystemDependency(SystemDependency):
         return [DependencyMethods.SYSTEM]
 
 
+class IntlBuiltinDependency(BuiltinDependency):
+    def __init__(self, name: str, env: 'Environment', kwargs: T.Dict[str, T.Any]):
+        super().__init__(name, env, kwargs)
+
+        if self.clib_compiler.has_function('ngettext', '', env)[0]:
+            self.is_found = True
+
+
+class IntlSystemDependency(SystemDependency):
+    def __init__(self, name: str, env: 'Environment', kwargs: T.Dict[str, T.Any]):
+        super().__init__(name, env, kwargs)
+
+        h = self.clib_compiler.has_header('libintl.h', '', env)
+        self.link_args =  self.clib_compiler.find_library('intl', env, [])
+
+        if h and self.link_args:
+            self.is_found = True
+
+
 @factory_methods({DependencyMethods.PKGCONFIG, DependencyMethods.CONFIG_TOOL, DependencyMethods.SYSTEM})
 def curses_factory(env: 'Environment',
                    for_machine: 'MachineChoice',
@@ -596,3 +615,10 @@ threads_factory = DependencyFactory(
     cmake_name='Threads',
     system_class=ThreadDependency,
 )
+
+intl_factory = DependencyFactory(
+    'intl',
+    [DependencyMethods.BUILTIN, DependencyMethods.SYSTEM],
+    builtin_class=IntlBuiltinDependency,
+    system_class=IntlSystemDependency,
+)