Enable the -Wundef warning for clang

webrtc/call/rtc_event_log_parser.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_CALL_RTC_EVENT_LOG_PARSER_H_
 #define WEBRTC_CALL_RTC_EVENT_LOG_PARSER_H_
 
 #include <string>
 #include <vector>
 
+#include "webrtc/base/ignore_wundef.h"
 #include "webrtc/call/rtc_event_log.h"
 #include "webrtc/video_receive_stream.h"
 #include "webrtc/video_send_stream.h"
 
 // Files generated at build-time by the protobuf compiler.
+RTC_PUSH_IGNORING_WUNDEF()
 #ifdef WEBRTC_ANDROID_PLATFORM_BUILD
 #include "external/webrtc/webrtc/call/rtc_event_log.pb.h"
 #else
 #include "webrtc/call/rtc_event_log.pb.h"
 #endif
+RTC_POP_IGNORING_WUNDEF()
 
 namespace webrtc {
 
 enum class MediaType;
 
 class ParsedRtcEventLog {
   friend class RtcEventLogTestHelper;
 
  public:
   enum EventType {
@@ skipping 75 matching lines @@
                              uint8_t* fraction_loss,
                              int32_t* total_packets) const;
 
  private:
   std::vector<rtclog::Event> events_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_CALL_RTC_EVENT_LOG_PARSER_H_