enforsed compilation with -W -Werror

diff --git a/skeletons/UTCTime.c b/skeletons/UTCTime.c
index e2f758e..5ce2708 100644
--- a/skeletons/UTCTime.c
+++ b/skeletons/UTCTime.c
@@ -29,6 +29,7 @@
 	  / sizeof(asn1_DEF_UTCTime_tags[0]),
 	1,	/* Single UNIVERSAL tag may be implicitly overriden */
 	-1,	/* Both ways are fine */
+	0	/* No specifics */
 };
 
 #endif	/* __NO_ASN_TABLE__ */
@@ -58,6 +59,9 @@
 		asn_app_consume_bytes_f *cb, void *app_key) {
 	const UTCTime_t *st = sptr;
 
+	(void)td;	/* Unused argument */
+	(void)ilevel;	/* Unused argument */
+
 	if(st && st->buf) {
 		char buf[32];
 		struct tm tm;
@@ -71,7 +75,7 @@
 			"%04d-%02d-%02d %02d:%02d%02d",
 			tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 			tm.tm_hour, tm.tm_min, tm.tm_sec);
-		assert(ret > 0 && ret < sizeof(buf));
+		assert(ret > 0 && ret < (int)sizeof(buf));
 		return cb(buf, ret, app_key);
 	} else {
 		return cb("<absent>", 8, app_key);
@@ -83,7 +87,8 @@
 	char buf[17+2];	/* "AAMMJJhhmmss+hhmm" = 17, + 2 = 19 */
 	GeneralizedTime_t gt;
 
-	if(!st || !st->buf || st->size < 11 || st->size > (sizeof(buf) - 2)) {
+	if(!st || !st->buf
+	|| st->size < 11 || st->size > ((int)sizeof(buf) - 2)) {
 		errno = EINVAL;
 		return -1;
 	}