itimerfix
if (itimerfix(&utv))
if (itimerfix(&utv)) {
if (itimerfix(&aitv->it_value) ||
else if (itimerfix(&aitv->it_interval) ||
if (itimerfix(&atv))
if (itimerfix(&atv))
if ((error = itimerfix(tv)) == 0)
int itimerfix(struct timeval *tv);