Enable the -Wundef warning for clang

webrtc/modules/audio_coding/test/utility.cc

 /*
  *  Copyright (c) 2011 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.
  */
 
 #include "utility.h"
 
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/audio_coding/include/audio_coding_module.h"
 #include "webrtc/modules/audio_coding/acm2/acm_common_defs.h"
 
 #define NUM_CODECS_WITH_FIXED_PAYLOAD_TYPE 13
 
 namespace webrtc {
 
 ACMTestTimer::ACMTestTimer()
     : _msec(0),
@@ skipping 264 matching lines @@
   printf("kVideoFrameKey...... %d\n", _numFrameTypes[kVideoFrameKey]);
   printf("kVideoFrameDelta.... %d\n", _numFrameTypes[kVideoFrameDelta]);
 }
 
 int32_t VADCallback::InFrameType(FrameType frame_type) {
   _numFrameTypes[frame_type]++;
   return 0;
 }
 
 }  // namespace webrtc