-#if HAVE_OFF64_T
-#define int64 off64_t
-#elif (SIZEOF_LONG == 8)
-#define int64 long
-#elif (SIZEOF_INT == 8)
-#define int64 int
-#elif HAVE_LONGLONG
-#define int64 long long
-#else
-/* As long as it gets... */
-#define int64 off_t
-#define NO_INT64
-#endif
-
-#if (SIZEOF_LONG == 8)
-#define uint64 unsigned long
-#elif (SIZEOF_INT == 8)
-#define uint64 unsigned int
-#elif HAVE_LONGLONG
-#define uint64 unsigned long long
+/* CAVEAT: on some systems, int64 will really be a 32-bit integer IFF
+ * that's the maximum size the file system can handle and there is no
+ * 64-bit type available. The rsync source must therefore take steps
+ * to ensure that any code that really requires a 64-bit integer has
+ * it (e.g. the checksum code uses two 32-bit integers for its 64-bit
+ * counter). */
+#if SIZEOF_OFF64_T == 8
+# define int64 off64_t
+# define SIZEOF_INT64 8
+#elif SIZEOF_LONG == 8
+# define int64 long
+# define SIZEOF_INT64 8
+#elif SIZEOF_INT == 8
+# define int64 int
+# define SIZEOF_INT64 8
+#elif SIZEOF_LONG_LONG == 8
+# define int64 long long
+# define SIZEOF_INT64 8
+#elif SIZEOF_OFF_T == 8
+# define int64 off_t
+# define SIZEOF_INT64 8
+#elif SIZEOF_INT > 8
+# define int64 int
+# define SIZEOF_INT64 SIZEOF_INT
+#elif SIZEOF_LONG > 8
+# define int64 long
+# define SIZEOF_INT64 SIZEOF_LONG
+#elif SIZEOF_LONG_LONG > 8
+# define int64 long long
+# define SIZEOF_INT64 SIZEOF_LONG_LONG