I have investigated the reasons for csound5 not
exiting cleanly on OS X. The problems seems to
be with portaudio not being able to close
the device, and Pa_AbortStream() not returning
ever. I tried Pa_CloseStream() and Pa_StopStream()
with the same results.

If I comment it out, csound exits although with an
ugly error message from the HAL, but at least it
does not hang.

So it seems that this is a bug in portaudio. That's
the problem of using someone else's code. Either
we go and try to debug it, which I'm not particularly
inclined to do, or we report it to the developers and
hope for the best. Any other suggestions?

Victor