Add include_examples GYP variable.

all.gyp

 # Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 {
   'variables': {
+    'include_examples%': 1,
     'include_tests%': 1,
     'webrtc_root_additional_dependencies': [],
   },
   'targets': [
     {
       'target_name': 'All',
       'type': 'none',
       'dependencies': [
         'webrtc/webrtc.gyp:*',
         'talk/libjingle.gyp:*',
-        'talk/libjingle_examples.gyp:*',
         '<@(webrtc_root_additional_dependencies)',
       ],
       'conditions': [
-        ['OS=="android"', {
+        ['include_examples==1', {
           'dependencies': [
+            'talk/libjingle_examples.gyp:*',
             'webrtc/webrtc_examples.gyp:*',
           ],
         }],
         ['include_tests==1', {
           'dependencies': [
             'talk/libjingle_tests.gyp:*',
           ],
         }],
       ],
     },
   ],
 }