> Introducing Rust is impossible for some platforms and hard for others. Please could someone elaborate on this.
There's at least one proprietary platform that supports Git built by via a vendor-provided C compiler, but for which no public documentation exists and therefore no LLVM support is possible. Ctrl+F for "NonStop" in https://lwn.net/Articles/998115/
It's probably not straightforward but the users of NonStop hardware have a lot of money so I'm sure they could find a way.