PkgConfigDependency: Don't try to resolve internal compiler libs

-lc -lm -ldl -lrt -lpthread are special linker arguments that should
never be resolved to on-disk libraries.

Closes https://github.com/mesonbuild/meson/issues/3879

3 files changed, 20 insertions, 6 deletions

diff --git a/mesonbuild/compilers/c.py b/mesonbuild/compilers/c.py
index 47cb568..5056b30 100644
--- a/mesonbuild/compilers/c.py
+++ b/mesonbuild/compilers/c.py
@@ -47,11 +47,14 @@ from .compilers import (
     RunResult,
 )
 
+gnu_compiler_internal_libs = ('m', 'c', 'pthread', 'dl', 'rt')
+
 
 class CCompiler(Compiler):
     library_dirs_cache = {}
     program_dirs_cache = {}
     find_library_cache = {}
+    internal_libs = gnu_compiler_internal_libs
 
     def __init__(self, exelist, version, is_cross, exe_wrapper=None, **kwargs):
         # If a child ObjC or CPP class has already set it, don't set it ourselves
@@ -903,10 +906,13 @@ class CCompiler(Compiler):
         # First try if we can just add the library as -l.
         # Gcc + co seem to prefer builtin lib dirs to -L dirs.
         # Only try to find std libs if no extra dirs specified.
-        if not extra_dirs:
+        if not extra_dirs or libname in self.internal_libs:
             args = ['-l' + libname]
             if self.links(code, env, extra_args=args):
                 return args
+            # Don't do a manual search for internal libs
+            if libname in self.internal_libs:
+                return None
         # Not found or we want to use a specific libtype? Try to find the
         # library file itself.
         patterns = self.get_library_naming(env, libtype)
@@ -1186,7 +1192,8 @@ class IntelCCompiler(IntelCompiler, CCompiler):
 class VisualStudioCCompiler(CCompiler):
     std_warn_args = ['/W3']
     std_opt_args = ['/O2']
-    ignore_libs = ('m', 'c', 'pthread')
+    ignore_libs = gnu_compiler_internal_libs
+    internal_libs = ()
 
     def __init__(self, exelist, version, is_cross, exe_wrap, is_64):
         CCompiler.__init__(self, exelist, version, is_cross, exe_wrap)
diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 25835a3..cb3ed23 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -661,6 +661,9 @@ class Compiler:
     # Libraries to ignore in find_library() since they are provided by the
     # compiler or the C library. Currently only used for MSVC.
     ignore_libs = ()
+    # Libraries that are internal compiler implementations, and must not be
+    # manually searched.
+    internal_libs = ()
     # Cache for the result of compiler checks which can be cached
     compiler_check_cache = {}
 
diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index f087db6..0e9a79d 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -621,12 +621,16 @@ class PkgConfigDependency(ExternalDependency):
                 # arguments as-is and then adding the libpaths at the end.
                 else:
                     args = None
-                if args:
+                if args is not None:
                     libs_found.add(lib)
                     # Replace -l arg with full path to library if available
-                    # else, library is provided by the compiler and can't be resolved
-                    if not args[0].startswith('-l'):
-                        lib = args[0]
+                    # else, library is either to be ignored, or is provided by
+                    # the compiler, can't be resolved, and should be used as-is
+                    if args:
+                        if not args[0].startswith('-l'):
+                            lib = args[0]
+                    else:
+                        continue
                 else:
                     # Library wasn't found, maybe we're looking in the wrong
                     # places or the library will be provided with LDFLAGS or