Fix some warnings in mod_secure_download.c

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2575 152afb58-edef-0310-8abb-c4023f1b3aa9

src/mod_secure_download.c

@@ -245,8 +245,8 @@ URIHANDLER_FUNC(mod_secdownload_uri_handler) {
 	}
 
 	/* timed-out */
-	if ( (srv->cur_ts > ts && srv->cur_ts - ts > p->conf.timeout) ||
-	     (srv->cur_ts < ts && ts - srv->cur_ts > p->conf.timeout) ) {
+	if ( (srv->cur_ts > ts && (unsigned int) (srv->cur_ts - ts) > p->conf.timeout) ||
+	     (srv->cur_ts < ts && (unsigned int) (ts - srv->cur_ts) > p->conf.timeout) ) {
 		/* "Gone" as the url will never be valid again instead of "408 - Timeout" where the request may be repeated */
 		con->http_status = 410;