Remove std:: prefixes from C functions in talk/.

std::memcpy -> memcpy for instance. This change was motivated by a
compile report complaining that std::rand() was used instead of rand(),
probably with a stdlib.h include instead of cstdlib. Use of C functions
without the std:: prefix is a lot more common, so removing std:: to
address this.

BUG=
R=tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9559004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5657 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/base/json.cc b/talk/base/json.cc
index af81e06..6b9fce1 100644
--- a/talk/base/json.cc
+++ b/talk/base/json.cc
@@ -28,9 +28,9 @@
 #include "talk/base/json.h"
 
 #include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
 
-#include <climits>
-#include <cstdlib>
 #include <sstream>
 
 bool GetStringFromJson(const Json::Value& in, std::string* out) {