Moved the AEC C code to be built using C++

webrtc/modules/audio_processing/aec/aec_core_neon.cc

 /*
  *  Copyright (c) 2014 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, neon version of speed-critical functions.
  *
  * Based on aec_core_sse2.c.
  */
 
 #include <arm_neon.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"
+}
 
 enum { kShiftExponentIntoTopMantissa = 8 };
 enum { kFloatExponentShift = 23 };
 
 __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 78 matching lines @@
   // The Newton-Raphson iteration:
   //     x[n+1] = x[n] * (3 - d * (x[n] * x[n])) / 2)
   // converges to (1/√d) if x0 is the result of VRSQRTE applied to d.
   //
   // Note: The precision did not improve after 2 iterations.
   for (i = 0; i < 2; i++) {
     x = vmulq_f32(vrsqrtsq_f32(vmulq_f32(x, x), s), x);
   }
   // sqrt(s) = s * 1/sqrt(s)
   return vmulq_f32(s, x);
-  ;
 }
 #endif  // WEBRTC_ARCH_ARM64
 
 static void ScaleErrorSignalNEON(int extended_filter_enabled,
                                  float normal_mu,
                                  float normal_error_threshold,
                                  float x_pow[PART_LEN1],
                                  float ef[2][PART_LEN1]) {
   const float mu = extended_filter_enabled ? kExtendedMu : normal_mu;
   const float error_threshold = extended_filter_enabled
@@ skipping 584 matching lines @@
 void WebRtcAec_InitAec_neon(void) {
   WebRtcAec_FilterFar = FilterFarNEON;
   WebRtcAec_ScaleErrorSignal = ScaleErrorSignalNEON;
   WebRtcAec_FilterAdaptation = FilterAdaptationNEON;
   WebRtcAec_OverdriveAndSuppress = OverdriveAndSuppressNEON;
   WebRtcAec_SubbandCoherence = SubbandCoherenceNEON;
   WebRtcAec_StoreAsComplex = StoreAsComplexNEON;
   WebRtcAec_PartitionDelay = PartitionDelayNEON;
   WebRtcAec_WindowData = WindowDataNEON;
 }