Even if the SCP were to use WineLib, developers would still need to have the MFC in order to compile. It may be possible for a few SCP developers to compile a lib and then distribute it along with the essential MFC headers, but only if that doesn't break any of the legal rules of the MFC package they're using.
I still think that wxWidgets is the way to go, I've already got the majority of the new GUI elements in place and work is underway to get them some function. Unfortunately, I've been preoccupied lately with work, (
) and I'm considering making a GitHub repo so that others may be able to chip in.
But then again, I could perhaps commit my changes so far to the fs2 SVN. I'll need to get my stuff sorted so that it'll play nice with the current build scripts, though.
From my reading of the legals page, to compile wineFRED you'd need to buy MVSC Pro anyway. And I don't know if a port to MFC+winelib would be any easier than a port to wxWidgets (maybe z64555 can comment further).
It might be more difficult to port to Winelib due to the face that *someone* would still need the MFC.
