Enable the -Wundef warning for clang

webrtc/modules/pacing/paced_sender_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.
  */
 
 #include <list>
 #include <memory>
 
-#include "testing/gmock/include/gmock/gmock.h"
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gmock.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/modules/pacing/paced_sender.h"
 #include "webrtc/system_wrappers/include/clock.h"
 
 using testing::_;
 using testing::Return;
 
 namespace webrtc {
 namespace test {
 
 static const int kTargetBitrateBps = 800000;
@@ skipping 1002 matching lines @@
 
   // No more probing packets.
   EXPECT_CALL(callback_, TimeToSendPadding(_, PacketInfo::kNotAProbe))
         .Times(1)
         .WillRepeatedly(Return(500));
   send_bucket_->Process();
 }
 
 }  // namespace test
 }  // namespace webrtc