Enable the -Wundef warning for clang

webrtc/common_audio/wav_header_unittest.cc

 /*
  *  Copyright (c) 2014 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 <limits>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/common_audio/wav_header.h"
 
 namespace webrtc {
 
 // Doesn't take ownership of the buffer.
 class ReadableWavBuffer : public ReadableWav {
  public:
   ReadableWavBuffer(const uint8_t* buf, size_t size)
       : buf_(buf),
         size_(size),
@@ skipping 290 matching lines @@
       ReadWavHeader(&r, &num_channels, &sample_rate, &format,
                     &bytes_per_sample, &num_samples));
   EXPECT_EQ(17u, num_channels);
   EXPECT_EQ(12345, sample_rate);
   EXPECT_EQ(kWavFormatALaw, format);
   EXPECT_EQ(1u, bytes_per_sample);
   EXPECT_EQ(123457689u, num_samples);
 }
 
 }  // namespace webrtc