fixed VS2008 project

bench.c => benchfn.c + benchzstd.c
wrong util.c from prior patch

and warnings :
C4127

programs/platform.h

@@ -26,6 +26,7 @@ extern "C" {
 #    define _CRT_SECURE_NO_DEPRECATE /* VS2005 - must be declared before <io.h> and <windows.h> */
 #    define snprintf sprintf_s       /* snprintf unsupported by Visual <= 2013 */
 #  endif
+#  pragma warning(disable : 4127)    /* disable: C4127: conditional expression is constant */
 #endif