Merge pull request #22600 from poettering/timestamp_is_set-more

make more use of timestamp_is_set()

src/libsystemd-network/lldp-neighbor.c

@@ -334,7 +334,7 @@ void lldp_neighbor_start_ttl(sd_lldp_neighbor *n) {
 
                 /* Use the packet's timestamp if there is one known */
                 base = triple_timestamp_by_clock(&n->timestamp, clock_boottime_or_monotonic());
-                if (base <= 0 || base == USEC_INFINITY)
+                if (!timestamp_is_set(base))
                         base = now(clock_boottime_or_monotonic()); /* Otherwise, take the current time */
 
                 n->until = usec_add(base, n->ttl * USEC_PER_SEC);