Enable the -Wundef warning for clang

webrtc/common_audio/resampler/resampler_unittest.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 "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gtest.h"
 
 #include "webrtc/common_audio/resampler/include/resampler.h"
 
 // TODO(andrew): this is a work-in-progress. Many more tests are needed.
 
 namespace webrtc {
 namespace {
 
 const int kNumChannels[] = {1, 2};
 const size_t kNumChannelsSize = sizeof(kNumChannels) / sizeof(*kNumChannels);
@@ skipping 108 matching lines @@
       } else {
         EXPECT_EQ(-1, rs_.Reset(kRates[i], kRates[j],
                                 kChannels));
       }
     }
   }
 }
 
 }  // namespace
 }  // namespace webrtc