Common: Cleanup memory and misc includes.

src/common/misc.cpp

@@ -2,12 +2,13 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
-#include "common/common_funcs.h"
+#include <cstddef>
 
 #ifdef _WIN32
 #include <windows.h>
 #else
-#include <string.h>
+#include <cerrno>
+#include <cstring>
 #endif
 
 // Neither Android nor OS X support TLS