Use gyp targets to link in X11 libraries instead of setting -lXfoo

content/content_plugin.gypi

 # Copyright (c) 2011 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.
 
 {
   'conditions': [
     ['enable_plugins==1', {
       'dependencies': [
         '../skia/skia.gyp:skia',
         '../third_party/WebKit/public/blink.gyp:blink',
@@ skipping 32 matching lines @@
         }],
         ['OS=="win"', {
           'include_dirs': [
             '<(DEPTH)/third_party/wtl/include',
           ],
         }],
         ['toolkit_uses_gtk == 1', {
           'dependencies': [
             '../build/linux/system.gyp:gtk',
           ],
-          'link_settings': {
-            'libraries': [
-              '-lXext',
-            ],
-          },
         }],
         ['use_x11 == 1', {
-          'link_settings': {
-            'libraries': [
-              '-lXext',
-            ],
-          },
+          'dependencies': [
+            '../build/linux/system.gyp:xext',
+          ],
         }],
       ],
     }],
   ],
 }