USEM_HAS_WAITERS
if (count & USEM_HAS_WAITERS)
if (count == USEM_HAS_WAITERS)
rv = casueword32(&sem->_count, 0, &count, USEM_HAS_WAITERS);
while (rv != -1 && count & USEM_HAS_WAITERS) {
count & ~USEM_HAS_WAITERS);