ETIME was returned by cond_timedwait (sic, the pre-POSIX1001b function) on 
Solaris 2.6 and 2.7. pthread_cond_timedwait on Solaris returns ETIMEDOUT.
The standard requirement is that the only additional return value
of pthred_cond_timedwait compared to pthread_cond_wait is ETIMEDOUT.
Let us not bloat the application code with redundant checks,
and if we're ever to work on a platform that returns a non-standard 
value, we should write a wrapper for that platform (like we do, e.g., for
Windows).