Fixed building with Visual Studio 2013

Added SDL_vacopy.h since it needs to be included after Windows headers

src/stdlib/SDL_string.c

@@ -27,6 +27,7 @@
 /* This file contains portable string manipulation functions for SDL */
 
 #include "SDL_stdinc.h"
+#include "SDL_vacopy.h"
 
 #if !defined(HAVE_VSSCANF) || !defined(HAVE_STRTOL) || !defined(HAVE_STRTOUL) || !defined(HAVE_STRTOD) || !defined(HAVE_STRTOLL) || !defined(HAVE_STRTOULL)
 #define SDL_isupperhex(X)   (((X) >= 'A') && ((X) <= 'F'))