[dholm]

I think OpenWatcom supports windows 3.x and it's quite a nice compiler if you are targeting older PC systems and don't require support for the latest versions of C or C++. You can easily use it to cross-compile from a modern OS and I used it a few years ago for a Hackathon where we implemented a simple demo that we built on Linux and ran in DOSBox with a CI-like pipeline (no Jenkins involved since it was just for fun).