Enable the -Wundef warning for clang

webrtc/modules/audio_coding/neteq/time_stretch_unittest.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
 // Unit tests for Accelerate and PreemptiveExpand classes.
 
 #include "webrtc/modules/audio_coding/neteq/accelerate.h"
 #include "webrtc/modules/audio_coding/neteq/preemptive_expand.h"
 
 #include <map>
 #include <memory>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
 #include "webrtc/modules/audio_coding/neteq/background_noise.h"
 #include "webrtc/modules/audio_coding/neteq/tools/input_audio_file.h"
 #include "webrtc/test/testsupport/fileutils.h"
 
 namespace webrtc {
 
 namespace {
 const size_t kNumChannels = 1;
@@ skipping 88 matching lines @@
 
 TEST_F(TimeStretchTest, AccelerateFastMode) {
   // TestAccelerate returns the total length change in samples.
   EXPECT_EQ(21400U, TestAccelerate(100, true));
   EXPECT_EQ(31, return_stats_[TimeStretch::kSuccess]);
   EXPECT_EQ(58, return_stats_[TimeStretch::kSuccessLowEnergy]);
   EXPECT_EQ(11, return_stats_[TimeStretch::kNoStretch]);
 }
 
 }  // namespace webrtc