depend on fontconfig when building for linux rather than x11

Source/platform/blink_platform.gyp

 #
 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 373 matching lines @@
       }],
       ['OS=="android"', {
         'sources/': [
           ['include', '^fonts/VDMXParser\\.cpp$'],
         ],
       }, { # OS!="android"
         'sources/': [
           ['exclude', 'Android\\.cpp$'],
         ],
       }],
-      ['use_x11 == 1', {
+      ['OS=="linux"', {
         'dependencies': [
           '<(DEPTH)/build/linux/system.gyp:fontconfig',
         ],
         'export_dependent_settings': [
           '<(DEPTH)/build/linux/system.gyp:fontconfig',
         ],
       }],
       ['use_default_render_theme==1', {
         'sources/': [
           ['exclude', 'scroll/ScrollbarThemeWin\\.(cpp|h)'],
@@ skipping 57 matching lines @@
           ['OS=="android"', {
             'cflags!': ['-mthumb'],
           }],
         ],
       },{  # target_arch!="arm"
         'type': 'none',
       }],
     ],
   }],
 }