Move GLIB_DISABLE_DEPRECATION_WARNINGS define to a more general place.

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")
 import("//tools/generate_library_loader/generate_library_loader.gni")
 
@@ skipping 125 matching lines @@
     name = "LibBrlapiLoader"
     output_h = "libbrlapi.h"
     output_cc = "libbrlapi_loader.cc"
     header = "<brlapi.h>"
     config = ":brlapi_config"
   }
 }
 
 pkg_config("gio_config") {
   packages = [ "gio-2.0" ]
-  defines = [ "USE_GIO" ]
+  # glib >=2.40 deprecate g_settings_list_schemas in favor of
+  # g_settings_schema_source_list_schemas. This function is not available on
+  # earlier versions that we still need to support (specifically, 2.32), so
+  # disable the warning with the GLIB_DISABLE_DEPRECATION_WARNINGS define.
+  # TODO(mgiuca): Remove this suppression when we drop support for Ubuntu 13.10
+  # (saucy) and earlier. Update the code to use
+  # g_settings_schema_source_list_schemas instead.
+  defines = [ "USE_GIO", "GLIB_DISABLE_DEPRECATION_WARNINGS" ]
   ignore_libs = true  # Loader generated below.
 }
 
 # This generates a target named "gio".
 generate_library_loader("gio") {
   name = "LibGioLoader"
   output_h = "libgio.h"
   output_cc = "libgio_loader.cc"
   header = "<gio/gio.h>"
   config = ":gio_config"
@@ skipping 20 matching lines @@
     "pci_alloc",
     "pci_init",
     "pci_cleanup",
     "pci_scan_bus",
     "pci_fill_info",
     "pci_lookup_name",
   ]
 }
 
 # Looking for libspeechd? Use //third_party/speech-dispatcher