It’s a cool idea, but I have had no luck so far building a working version of ioquake3 so that’s out of my league.
Anyway, I’m writing here to ask for help with GZDoom, it ships with an SDL2-based Launcher that freezes on startup. I have no experience with SDL and have had no luck fixing this so far. If somebody wants to have a look at it you can start from this pull request at haikuports, the related fork has all that’s needed to compile it from the latest source.