Use nixos cross-compilation to provide binaries for other architectures

[mrcjkb]

Here's a wild idea:

On NixOS, it's super easy to cross-compile for other architectures (even Windows).

Perhaps we can leverage that capability to provide binary rocks (and luarocks!) for all sorts of systems.

It won't work with GitHub Actions and would have to be run manually on a NixOS machine that's configured accordingly.

[mrcjkb]

Related:

• https://github.com/nvim-neorocks/rocks.nvim/issues/487