envconfig: add pkg_config_path property

In order to unify the use of sysroot in the cross-file,
the pkg_config_path can now be passed directly in the file.

mesonbuild/dependencies/base.py

@@ -693,7 +693,12 @@ def _call_pkgbin(self, args, env=None):
         sysroot = self.env.properties[self.for_machine].get_sys_root()
         if sysroot:
             env['PKG_CONFIG_SYSROOT_DIR'] = sysroot
-        new_pkg_config_path = ':'.join([p for p in extra_paths])
+        pkg_config_path_prop =  self.env.properties[self.for_machine].get_pkg_config_path()
+
+        if pkg_config_path_prop:
+            new_pkg_config_path = ':'.join([p for p in pkg_config_path_prop])
+        else:
+            new_pkg_config_path = ':'.join([p for p in extra_paths])
         mlog.debug('PKG_CONFIG_PATH: ' + new_pkg_config_path)
         env['PKG_CONFIG_PATH'] = new_pkg_config_path
 

mesonbuild/envconfig.py

@@ -140,6 +140,9 @@ def get_root(self) -> T.Optional[T.Union[str, T.List[str]]]:
     def get_sys_root(self) -> T.Optional[T.Union[str, T.List[str]]]:
         return self.properties.get('sys_root', None)
 
+    def get_pkg_config_path(self) -> T.Optional[T.Union[str, T.List[str]]]:
+        return self.properties.get('pkg_config_path', None)
+
     def __eq__(self, other: T.Any) -> 'T.Union[bool, NotImplemented]':
         if isinstance(other, type(self)):
             return self.properties == other.properties