Fix off_t printf warning.

src/sbbs3/websrvr.c

@@ -1499,7 +1499,7 @@ static off_t sock_sendfile(http_session_t *session,char *path, off_t start, off_
 	else {
 		if(start || end) {
 			if(lseek(file, start, SEEK_SET)==-1) {
-				lprintf(LOG_WARNING,"%04d !ERROR %d seeking to position %lu in %s",session->socket,ERROR_VALUE,start,path);
+				lprintf(LOG_WARNING,"%04d !ERROR %d seeking to position %" PRIuOFF " in %s",session->socket,ERROR_VALUE,start,path);
 				close(file);
 				return(0);
 			}