sldns_serial_arithmetics_time
int64_t secs_since_epoch = sldns_serial_arithmetics_time(time, now);
time_t secs_since_epoch = sldns_serial_arithmetics_time(time, now);
int64_t secs_since_epoch = sldns_serial_arithmetics_time(time, now);
time_t secs_since_epoch = sldns_serial_arithmetics_time(time, now);