For those interested in Mac OS X development, I created a CoreAudio based sample program that shows how to setup an output AudioQueue with buffers and using a callback to supply it with audio data (a square wave in this case.)
This mirrors the DirectSound setup and playback code of the win32 version of HH. This code is stand-alone, but I'm looking at creating a full Mac OS X shell for HH as well.
This sample uses some C++11 features such as auto type deduction and std::thread to have the app wait for a few seconds so you can hear something but otherwise is very straightforward.
Full, commented code with command line build args here:
https://gist.github.com/zenmumbler/b5bbabef1df3efe1a5df
Have fun.