[MLton] filedes = int (was: Stack size?)

[Henry Cejtin]

I certainly agree that we don't want to duplicate the code in the libc section
of sleep.  I just don't think that there is a good reason to pitch the
fractional-second part of the sleep so-called system call.  nanosleep is
also in Posix.  I couldn't see what section, but that was enough to tell me
that it would be ok to just call nanosleep() (no other computation, just
converting the Time.time arg to the struct timespec).