futex_twait
assert(futex_twait(shlock, 0, CLOCK_REALTIME, &tmo,
assert(futex_twait(shlock, 0, 0, NULL, 0) == 0);
assert(futex_twait(shlock, 0, CLOCK_REALTIME, &tmo,
assert(futex_twait(&lock, 0, 0, NULL, 0) == -1);
assert(futex_twait((void *)0xdeadbeef, 1, 0, NULL, 0) == -1);
assert(futex_twait(&lock, 1, 0, NULL, 0) == -1);
assert(futex_twait(&lock, 0, CLOCK_REALTIME, &tmo, 0) == -1);
assert(futex_twait(&lock, 0, 0, NULL, 0) == 0);
assert(futex_twait(shlock, 0, 0, NULL, 0) == 0);