use curl_off_t instead of off_t!

lib/setup.h

@@ -244,21 +244,4 @@ typedef struct hostent Curl_addrinfo;
 typedef struct in_addr Curl_ipconnect;
 #endif
 
-#if 0
-#if (SIZEOF_OFF_T > 4)
-/* off_t is bigger than 4 bytes, and that makes it our prefered variable
-   type for filesizes */
-typedef off_t filesize_t;
-#else
-#ifdef HAVE_LONGLONG
-/* we have long long, use this for filesizes internally */
-typedef long long filesize_t;
-#else
-/* small off_t and no long long, no support for large files :-( */
-typedef long filesize_t;
-#endif /* didn't have long long */
-#endif /* sizeof wasn't bigger than 4 */
-
-#endif /* 0 */
-
 #endif /* __CONFIG_H */