dependencies: Add command line option for pkg_config_path

This creates a new command line option to store pkg_config_path into,
and store the environment variable into that option. Currently this
works like the environment variable, for both cross and native targets.

mesonbuild/coredata.py

@@ -270,7 +270,6 @@ class CoreData:
         self.cross_compilers = OrderedDict()
         self.deps = OrderedDict()
         # Only to print a warning if it changes between Meson invocations.
-        self.pkgconf_envvar = os.environ.get('PKG_CONFIG_PATH', '')
         self.config_files = self.__load_config_files(options.native_file)
         self.libdir_cross_fixup()
 
@@ -504,6 +503,12 @@ class CoreData:
         # languages and setting the backend (builtin options must be set first
         # to know which backend we'll use).
         options = {}
+
+        # Some options default to environment variables if they are
+        # unset, set those now. These will either be overwritten
+        # below, or they won't.
+        options['pkg_config_path'] = os.environ.get('PKG_CONFIG_PATH', '').split(':')
+
         for k, v in env.cmd_line_options.items():
             if subproject:
                 if not k.startswith(subproject + ':'):
@@ -789,6 +794,7 @@ builtin_options = {
     'optimization':    BuiltinOption(UserComboOption, 'Optimization level', '0', choices=['0', 'g', '1', '2', '3', 's']),
     'debug':           BuiltinOption(UserBooleanOption, 'Debug', True),
     'wrap_mode':       BuiltinOption(UserComboOption, 'Wrap mode', 'default', choices=['default', 'nofallback', 'nodownload', 'forcefallback']),
+    'pkg_config_path': BuiltinOption(UserArrayOption, 'List of additional paths for pkg-config to search', []),
 }
 
 # Special prefix-dependent defaults for installation directories that reside in

mesonbuild/dependencies/base.py

@@ -609,11 +609,16 @@ class PkgConfigDependency(ExternalDependency):
         return rc, out
 
     def _call_pkgbin(self, args, env=None):
+        # Always copy the environment since we're going to modify it
+        # with pkg-config variables
         if env is None:
-            fenv = env
-            env = os.environ
+            env = os.environ.copy()
         else:
-            fenv = frozenset(env.items())
+            env = env.copy()
+
+        extra_paths = self.env.coredata.get_builtin_option('pkg_config_path')
+        env['PKG_CONFIG_PATH'] = ':'.join([p for p in extra_paths])
+        fenv = frozenset(env.items())
         targs = tuple(args)
         cache = PkgConfigDependency.pkgbin_cache
         if (self.pkgbin, targs, fenv) not in cache:

mesonbuild/msetup.py

@@ -149,13 +149,6 @@ class MesonApp:
                 sys.exit(1)
         return src_dir, build_dir
 
-    def check_pkgconfig_envvar(self, env):
-        curvar = os.environ.get('PKG_CONFIG_PATH', '')
-        if curvar != env.coredata.pkgconf_envvar:
-            mlog.warning('PKG_CONFIG_PATH has changed between invocations from "%s" to "%s".' %
-                         (env.coredata.pkgconf_envvar, curvar))
-            env.coredata.pkgconf_envvar = curvar
-
     def generate(self):
         env = environment.Environment(self.source_dir, self.build_dir, self.options)
         mlog.initialize(env.get_log_dir(), self.options.fatal_warnings)
@@ -169,7 +162,6 @@ class MesonApp:
         mlog.debug('Main binary:', sys.executable)
         mlog.debug('Python system:', platform.system())
         mlog.log(mlog.bold('The Meson build system'))
-        self.check_pkgconfig_envvar(env)
         mlog.log('Version:', coredata.version)
         mlog.log('Source dir:', mlog.bold(self.source_dir))
         mlog.log('Build dir:', mlog.bold(self.build_dir))

run_unittests.py

@@ -4837,9 +4837,9 @@ endian = 'little'
         testdir = os.path.join(self.unit_test_dir, '58 pkgconfig relative paths')
         pkg_dir = os.path.join(testdir, 'pkgconfig')
         self.assertTrue(os.path.exists(os.path.join(pkg_dir, 'librelativepath.pc')))
-        os.environ['PKG_CONFIG_PATH'] = pkg_dir
 
         env = get_fake_env(testdir, self.builddir, self.prefix)
+        env.coredata.set_options({'pkg_config_path': pkg_dir}, '')
         kwargs = {'required': True, 'silent': True}
         relative_path_dep = PkgConfigDependency('librelativepath', env, kwargs)
         self.assertTrue(relative_path_dep.found())
@@ -5068,6 +5068,11 @@ endian = 'little'
                 # Assert that
                 self.assertEqual(len(line.split(lib)), 2, msg=(lib, line))
 
+    @skipIfNoPkgconfig
+    def test_pkg_config_option(self):
+        testdir = os.path.join(self.unit_test_dir, '55 pkg_config_path option')
+        self.init(testdir, extra_args=['-Dpkg_config_path=' + os.path.join(testdir, 'extra_path')])
+
 
 def should_run_cross_arm_tests():
     return shutil.which('arm-linux-gnueabihf-gcc') and not platform.machine().lower().startswith('arm')

test cases/unit/55 pkg_config_path option/extra_path/totally_made_up_dep.pc

@@ -0,0 +1,7 @@
+prefix=/
+libdir=${prefix}/lib
+includedir=${prefix}/include
+
+Name: totally_made_up_dep
+Description: completely and totally made up for a test case
+Version: 1.2.3

test cases/unit/55 pkg_config_path option/meson.build

@@ -0,0 +1,3 @@
+project('pkg_config_path option')
+
+dependency('totally_made_up_dep', method : 'pkg-config')