[plt-scheme] Non-Carbon MacOS 9 MzSchemeLib?

Hello!  I still haven't had any luck building a non-Carbon version of
MzSchemeLib for MacOS 9 (Carbon is missing some APIs which exist in OS 9
and OS X, and so I can't use it).

Is there any hope of getting this to work with a few day's effort, or
should I just give up now?

Cheers,
Eric