If threads A and B queue operations simultaneously, it would
previously be possible for B's operation to complete and wake thread A
from cond_wait, which would fail its condition check and then deadlock
as only thread B is awoken when A's operation completes.

This change wakes all threads waiting on the cond var, and each thread
already checks its condition before choosing to continue.
Signed-off-by: Andrew Eikum <aeikum@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>