per POSIX, the EINTR condition is an optional error for these
functions, not a mandatory one. since old kernels (pre-2.6.22) failed
to honor SA_RESTART for the futex syscall, it's dangerous to trust
EINTR from the kernel. thankfully POSIX offers an easy way out.
a_cas(sem->__val, 0, -1);
r = __timedwait(sem->__val, -1, CLOCK_REALTIME, at, cleanup, sem->__val+1, sem->__val[2]);
a_dec(sem->__val+1);
a_cas(sem->__val, 0, -1);
r = __timedwait(sem->__val, -1, CLOCK_REALTIME, at, cleanup, sem->__val+1, sem->__val[2]);
a_dec(sem->__val+1);