cnd_init
extern int cnd_init(cnd_t *);
VERIFY3S(cnd_init(&broadcast_cnd), ==, thrd_success);
VERIFY3S(cnd_init(&signal_cnd), ==, thrd_success);
VERIFY3S(cnd_init(&cnd), ==, thrd_success);
VERIFY3S(cnd_init(&ct_cnd), ==, thrd_success);
VERIFY3S(cnd_init(&co_cnd), ==, thrd_success);