Make WARN_UNUSED_RESULT a no-op on gcc

webrtc/base/swap_queue.h

 /*
  *  Copyright (c) 2015 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.
  */
 
@@ skipping 100 matching lines @@
     next_read_index_ = 0;
     num_elements_ = 0;
   }
 
   // Inserts a "full" T at the back of the queue by swapping *input with an
   // "empty" T from the queue.
   // Returns true if the item was inserted or false if not (the queue was full).
   // When specified, the T given in *input must pass the ItemVerifier() test.
   // The contents of *input after the call are then also guaranteed to pass the
   // ItemVerifier() test.
-  bool Insert(T* input) WARN_UNUSED_RESULT {
+  bool Insert(T* input) RTC_WARN_UNUSED_RESULT {
     RTC_DCHECK(input);
 
     rtc::CritScope cs(&crit_queue_);
 
     RTC_DCHECK(queue_item_verifier_(*input));
 
     if (num_elements_ == queue_.size()) {
       return false;
     }
 
@@ skipping 12 matching lines @@
 
     return true;
   }
 
   // Removes the frontmost "full" T from the queue by swapping it with
   // the "empty" T in *output.
   // Returns true if an item could be removed or false if not (the queue was
   // empty). When specified, The T given in *output must pass the ItemVerifier()
   // test and the contents of *output after the call are then also guaranteed to
   // pass the ItemVerifier() test.
-  bool Remove(T* output) WARN_UNUSED_RESULT {
+  bool Remove(T* output) RTC_WARN_UNUSED_RESULT {
     RTC_DCHECK(output);
 
     rtc::CritScope cs(&crit_queue_);
 
     RTC_DCHECK(queue_item_verifier_(*output));
 
     if (num_elements_ == 0) {
       return false;
     }
 
@@ skipping 37 matching lines @@
 
   // queue_.size() is constant.
   std::vector<T> queue_ GUARDED_BY(crit_queue_);
 
   RTC_DISALLOW_COPY_AND_ASSIGN(SwapQueue);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_BASE_SWAP_QUEUE_H_