Thought about Cosmopolitan C
The Cosmopolitan C project just released v3.0 of the library. It's a technical marvel - compile a single binary that runs on 6 OSes, across 2 architectures, and also on bare metal.
It occurs to me - since BIOS is supported, one could probably compile Firefox with cosmoc, and get the METAL operating system from Birth & Death of JavaScript.
If you haven't seem that talk, do yourself a favor and watch it, and then click around on the cosmo c project website.