Cosmopolitan https://github.com/jart/cosmopolitan and https://justine.lol/cosmopolitan/index.html
Some genius realized that you can actually embed valid win32 programs inside valid posix shell scripts, and found a way to make a C cross-platform solution out of it, meaning that you can write C programs that compile to a single executable that will run on (quoting the site) Linux + Mac + Windows + FreeBSD + OpenBSD + NetBSD + BIOS
It all started from this post.