aarch64-linux-aarch64-unknown-linux-gnutargeti686-linux-i686-unknown-linux-gnutargetx86_64-linux-x86_64-unknown-linux-gnutarget
These toolchains become a no-op toolchains if the target architecture is the same as native one.
These toolchains use Nixpkgs cross-compilation packages, which are not guaranteed to be cached, so building them might take a long time. Binary cache is required to make it practical.
These toolchains don't work on MacOS right now (unimplemented in Nixpkgs).