To be honest it has been a long time since I worked with mfcs (20 years+), so maybe someone else can offer another avenue. But I am not aware of any "conversion" method other than writing new classes with the same interface and/or function provided by the mfcs.
The mfcs are very non-portable as I recall, largely because they bind tightly to Window$ core/kernel types and features.
*** Added comment: I just did a quick search and did not see any other path prominently mentioned. It will likely be a lot of work and involve more than a simple one-to-one code rewrite for a large application, but is of course doable.
Last edited by astrogeek; 08-17-2015 at 03:20 AM.