diff --git a/programs/xxhash.c b/programs/xxhash.c
index 352d1e540..2a66e251a 100644
--- a/programs/xxhash.c
+++ b/programs/xxhash.c
@@ -123,7 +123,7 @@ static void* XXH_memcpy(void* dest, const void* src, size_t size) { return memcp
 ***************************************/
 #ifndef MEM_MODULE
 # define MEM_MODULE
-# if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
+# if !defined (__VMS) && ( defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */ )
 #   include <stdint.h>
     typedef uint8_t  BYTE;
     typedef uint16_t U16;