gn: Pass pkg_config_args when invoking pkg_config_script.

build/config/linux/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/linux/pkg_config.gni")
 import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 
 # This is included by reference in the //build/config/compiler config that
@@ skipping 105 matching lines @@
 
 # CrOS doesn't install GTK, gconf or any gnome packages.
 if (!is_chromeos && use_gconf) {
   # These packages should _only_ be expected when building for a target.
   # If these extra checks are not run, gconf is required when building host
   # tools for a CrOS build.
   if (current_toolchain == default_toolchain) {
     pkg_config("atk") {
       packages = [ "atk" ]
       atk_lib_dir = exec_script(pkg_config_script,
-                                [
-                                  "--libdir",
-                                  "atk",
-                                ],
+                                pkg_config_args + [
+                                      "--libdir",
+                                      "atk",
+                                    ],
                                 "string")
       defines = [ "ATK_LIB_DIR=\"$atk_lib_dir\"" ]
     }
 
     # gn orders flags on a target before flags from configs. The default config
     # adds -Wall, and these flags have to be after -Wall -- so they need to
     # come from a config and can't be on the target directly.
     config("atk_warnings") {
       cflags = [
         # glib uses the pre-c++11 typedef-as-static_assert hack.
         "-Wno-unused-local-typedef",
 
         # G_DEFINE_TYPE automatically generates a *get_instance_private
         # inline function after glib 2.37. That's unused. Prevent to
         # complain about it.
         "-Wno-unused-function",
       ]
     }
 
     pkg_config("gconf") {
       packages = [ "gconf-2.0" ]
       defines = [ "USE_GCONF" ]
     }
   }
 }