Moved the aec_rdft*.c files to be built using C++

webrtc/modules/audio_processing/aec/aec_core_sse2.cc

 /*
  *  Copyright (c) 2011 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.
  */
 
 /*
  * The core AEC algorithm, SSE2 version of speed-critical functions.
  */
 
 #include <emmintrin.h>
 #include <math.h>
 #include <string.h>  // memset
 
 extern "C" {
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
 }
 #include "webrtc/modules/audio_processing/aec/aec_common.h"
 #include "webrtc/modules/audio_processing/aec/aec_core_internal.h"
-extern "C" {
 #include "webrtc/modules/audio_processing/aec/aec_rdft.h"
-}
 
 namespace webrtc {
 
 __inline static float MulRe(float aRe, float aIm, float bRe, float bIm) {
   return aRe * bRe - aIm * bIm;
 }
 
 __inline static float MulIm(float aRe, float aIm, float bRe, float bIm) {
   return aRe * bIm + aIm * bRe;
 }
@@ skipping 701 matching lines @@
   WebRtcAec_FilterFar = FilterFarSSE2;
   WebRtcAec_ScaleErrorSignal = ScaleErrorSignalSSE2;
   WebRtcAec_FilterAdaptation = FilterAdaptationSSE2;
   WebRtcAec_OverdriveAndSuppress = OverdriveAndSuppressSSE2;
   WebRtcAec_SubbandCoherence = SubbandCoherenceSSE2;
   WebRtcAec_StoreAsComplex = StoreAsComplexSSE2;
   WebRtcAec_PartitionDelay = PartitionDelaySSE2;
   WebRtcAec_WindowData = WindowDataSSE2;
 }
 }  // namespace webrtc