_lwp_cond_reltimedwait
int _lwp_cond_reltimedwait(lwp_cond_t *, lwp_mutex_t *, timespec_t *);
return (_lwp_cond_reltimedwait(cv, mp, &tslocal));
err = _lwp_cond_reltimedwait(cv, &mp->m_lock, &ts);
int _lwp_cond_reltimedwait(lwp_cond_t *, lwp_mutex_t *, timespec_t *);