Add do_sig_wait parameter. Wait for signal_arrived if set to true.
Return WAIT_SIGNALED if signal arrived.
(pthread_cond::wait): Accomodate change to pthread::cancelable_wait.
(pthread::join): Ditto.
(semaphore::_timedwait): Ditto.
(semaphore::_wait): Ditto. Change to return int to allow status
feedback.
(semaphore::wait): Return return value from semaphore::_wait.
* thread.h (WAIT_SIGNALED): New definition.
(pthread::cancelable_wait): Change declaration. Define do_sig_wait
as false by default to not interfere with existing calls accidentally.
(semaphore::_wait): Declare int.
c9a76075f5