I've been having similar issues with Windows 3.11; trying to boot a qemu image I made a few years back and it looks like networking has died in the meantime, and another image crashes when it exceeds some small amount of RAM usage. But at least there's nothing stopping us from running an older linux in qemu to easily use an older qemu version that way, avoiding the hassle of having to patch the source to work with recent versions of its dependencies.