macOS: pthread_barrier_wait impropper wait condition

[Youw]

Found by Coverity:

static int pthread_barrier_wait(pthread_barrier_t *barrier)
{
 //  	lock_acquire: Calling pthread_mutex_lock acquires lock pthread_barrier.mutex.
        pthread_mutex_lock(&barrier->mutex);
        ++(barrier->count);
//   	if_insufficient: This if cannot adequately check the wait condition, as it does not cause the thread to wait again if the wait ends due to a spurious wakeup.
        if(barrier->count >= barrier->trip_count)
        {
                barrier->count = 0;
                pthread_cond_broadcast(&barrier->cond);
                pthread_mutex_unlock(&barrier->mutex);
                return 1;
        }
        else
        {
  
// CID undefined (#1 of 1): Data race condition (BAD_CHECK_OF_WAIT_COND)
// wait_cond_improperly_checked: The wait condition prompting the wait upon pthread_barrier.mutex is not checked correctly. If a spurious wakeup occurs, the thread could continue its task before the wait condition is satisfied.
	Refactor the code to protect the call to wait with a loop that rechecks the wait condition inside the locked region.
                pthread_cond_wait(&barrier->cond, &(barrier->mutex));
                pthread_mutex_unlock(&barrier->mutex);
                return 0;
        }
}