GET_CONDVAR_WAITERS 1182 thread_sync.c      VALUE waiters = GET_CONDVAR_WAITERS(self);
GET_CONDVAR_WAITERS 1205 thread_sync.c      wakeup_first_thread(GET_CONDVAR_WAITERS(self));
GET_CONDVAR_WAITERS 1218 thread_sync.c      wakeup_all_threads(GET_CONDVAR_WAITERS(self));