+#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