Worked out of the box on Snow Leopard, with one wrinkle.
When I tried it out it would load all the hacks and emit the command, but not run it.
The default mzscheme location in OSX has spaces:
/Applications/PLT\ Scheme\ v4.2.2/bin/mzscheme
but exec on that runs nothing and gives no error. Turns out spaces need to be escaped inside $mzscheme.
I reset that config variable and it worked. (mzscheme as already in my path).
