ok, this is The Last Time mucking with the dang

offset overflow check.  the expression has been simplified and if
this causes warnings on any platform now i'm gonna go postal.

lib/dns/journal.c

@@ -1263,19 +1263,17 @@ journal_next(dns_journal_t *j, journal_pos_t *pos) {
 	 */
 	if (xhdr.serial0 != pos->serial) {
 		isc_log_write(JOURNAL_COMMON_LOGARGS, ISC_LOG_ERROR,
-				 "%s: journal file corrupt: "
-				 "expected serial %u, got %u",
-				 j->filename,
-				 pos->serial, xhdr.serial0);
+			      "%s: journal file corrupt: "
+			      "expected serial %u, got %u",
+			      j->filename, pos->serial, xhdr.serial0);
 		return (ISC_R_UNEXPECTED);
 	}
 
 	/*
 	 * Check for offset wraparound.
 	 */
-	if (xhdr.size + sizeof(journal_rawxhdr_t) > ISC_OFFSET_MAXIMUM ||
-           ISC_OFFSET_MAXIMUM - xhdr.size - sizeof(journal_rawxhdr_t)
-           < pos->offset) {
+	if ((isc_offset_t)(pos->offset + sizeof(journal_rawxhdr_t) + xhdr.size)
+	    < pos->offset) {
 		isc_log_write(JOURNAL_COMMON_LOGARGS, ISC_LOG_ERROR,
 			      "%s: offset too large", j->filename);
 		return (ISC_R_UNEXPECTED);