Enable the -Wundef warning for clang

webrtc/video/full_stack.cc

 /*
  *  Copyright (c) 2013 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 <stdio.h>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/test/gtest.h"
 #include "webrtc/video/video_quality_test.h"
 
 namespace webrtc {
 
 static const int kFullStackTestDurationSecs = 60;
 
 class FullStackTest : public VideoQualityTest {
  public:
   void RunTest(const VideoQualityTest::Params &params) {
     RunWithAnalyzer(params);
@@ skipping 213 matching lines @@
       {},
       {true, 10},
       {"screenshare_slides_vp9_2sl", 0.0, 0.0, kFullStackTestDurationSecs},
       {},
       false,
       {std::vector<VideoStream>(), 0, 2, 1}};
   RunTest(screenshare);
 }
 #endif  // !defined(RTC_DISABLE_VP9)
 }  // namespace webrtc