Don't assume UINT64_C available

[Albert Chin]

Tru64 UNIX doesn't have the UINT64_C() macro.

-- 
albert chin (china at thewrittenword.com)

-- snip snip
2003-09-02  Albert Chin-A-Young (china at thewrittenword.com>

	* include/types.h: Provide replacement UINT64_C() macro
	if unavailable.

--- include/types.h.orig	Tue Sep  2 13:09:56 2003
+++ include/types.h	Tue Sep  2 13:10:54 2003
@@ -103,7 +103,11 @@
 #undef u64	    /* maybe there is a macro with this name */
 #if SIZEOF_UINT64_T == 8
 typedef uint64_t u64;
+#ifdef UINT64_C
 #define U64_C(c) (UINT64_C(c))
+#else
+#define U64_C(c) (c ## ULL)
+#endif
 #define HAVE_U64_TYPEDEF
 #elif SIZEOF_UNSIGNED_INT == 8
 typedef unsigned int u64;