* some systems (e.g. Mac OS X).
*/
# ifndef PRIu64
-# if (__STDC_VERSION__ >= 199901L)
-# include <inttypes.h>
+# ifdef __STDC_VERSION__
+# if (__STDC_VERSION__ >= 199901L)
+# include <inttypes.h>
+# endif
# endif
# ifndef PRIu64
# define PRIu64 "lu"