Re: pthread_cond_signal/broadcast: necessary to hold mutex?

Feels like bug report time to me.

Also, our man page talks about "changing the mutex" associated with the
pthread_cond_t, but as I read POSIX there is no rule that you can't have
N threads waiting on the same condvar each with a different mutex.  The
mutex is just about the wait caller, holding it on entry and getting it
back later, with it released in between.

It would be interesting to see what the code does; this could just be a
doc issue.