Switch C++-style C headers with their C equivalents.

The C++ headers define the C functions within the std:: namespace, but
we mainly don't use the std:: namespace for C functions. Therefore we
should include the C headers.

BUG=1833
R=tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1917004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4486 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/dsp_helper.cc b/webrtc/modules/audio_coding/neteq4/dsp_helper.cc
index ebb3966..f972fc5 100644
--- a/webrtc/modules/audio_coding/neteq4/dsp_helper.cc
+++ b/webrtc/modules/audio_coding/neteq4/dsp_helper.cc
@@ -11,9 +11,9 @@
 #include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
 
 #include <assert.h>
+#include <string.h>  // Access to memset.
 
 #include <algorithm>  // Access to min, max.
-#include <cstring>  // Access to memset.
 
 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"