Rustaceans at the border

If this were my project (and maybe 0.1% the size), I'd migrate the rest of the existing codebase to use Cargo and Rust build scripts, rather than the other way around (trying to get Cargo to fit into makefiles/something else), since other parts of the kernel are probably going to eventually be rewritten in Rust as well.

That doesn't exactly sound feasible here, but it's a nice thought. imho, it would be an almost-all-around win for Cargo to become more interoperable with existing build systems, but it could also encourage laziness or tricky setups.