dependencies: Add function to strip system -L paths

PkgConfig automatically removes -L paths from libdirs if the -L points
to a system path. It knows what these paths are by taking this as a
configure option at build time, which the distro maintainers set
appropriately and everything works. This allows one to have two
versions of a package installed, a system and non system, and then
override PKG_CONFIG_PATH to use the non system version, and everything
just works. For non-pkgconfig dependencies (such as LLVM) meson needs to
strip these themselves to avoid breaking the above use case.

1 files changed, 11 insertions, 0 deletions

diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index 0d9742d..9913a0b 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -640,3 +640,14 @@ def find_external_dependency(name, env, kwargs):
         raise pkg_exc
     mlog.log('Dependency', mlog.bold(name), 'found:', mlog.red('NO'))
     return pkgdep
+
+
+def strip_system_libdirs(environment, link_args):
+    """Remove -L<system path> arguments.
+
+    leaving these in will break builds where a user has a version of a library
+    in the system path, and a different version not in the system path if they
+    want to link against the non-system path version.
+    """
+    exclude = {'-L{}'.format(p) for p in environment.get_compiler_system_dirs()}
+    return [l for l in link_args if l not in exclude]