Enable the -Wundef warning for clang

webrtc/modules/audio_processing/test/aec_dump_based_simulator.h

 /*
  *  Copyright (c) 2016 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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_TEST_AEC_DUMP_BASED_SIMULATOR_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_TEST_AEC_DUMP_BASED_SIMULATOR_H_
 
 #include "webrtc/modules/audio_processing/test/audio_processing_simulator.h"
 
 #include "webrtc/base/constructormagic.h"
+#include "webrtc/base/ignore_wundef.h"
 
+RTC_PUSH_IGNORING_WUNDEF()
 #ifdef WEBRTC_ANDROID_PLATFORM_BUILD
 #include "external/webrtc/webrtc/modules/audio_processing/debug.pb.h"
 #else
 #include "webrtc/modules/audio_processing/debug.pb.h"
 #endif
+RTC_POP_IGNORING_WUNDEF()
 
 namespace webrtc {
 namespace test {
 
 // Used to perform an audio processing simulation from an aec dump.
 class AecDumpBasedSimulator final : public AudioProcessingSimulator {
  public:
   explicit AecDumpBasedSimulator(const SimulationSettings& settings)
       : AudioProcessingSimulator(settings) {}
   ~AecDumpBasedSimulator() override {}
@@ skipping 20 matching lines @@
   FILE* dump_input_file_;
   InterfaceType interface_used_ = InterfaceType::kNotSpecified;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(AecDumpBasedSimulator);
 };
 
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_TEST_AEC_DUMP_BASED_SIMULATOR_H_