For void: https://github.com/voidlinux/void-packages/issues/4570

And alpine: http://pkgs.alpinelinux.org/packages?name=rust*&branch=&repo...

https://github.com/rust-lang/rust/issues/31322#issuecomment-... is the latest news on the subject. It's not impossible, but we're not sure _how_ we want to make it easy. The real issue is the bootstrapping, my understanding is that cross-compiling a musl compiler from a gnu compiler does work today, which is how those packages were made.