You can now link rust code to C code without a special runtime setup.

https://github.com/rust-lang/rust/commit/0efafac398ff7f28c5f0fe756c15b9008b3e0534

This is a very big attitude difference between Go (where mostly the approach is "rewrite the world in Go") and Rust (where it's becoming "we really need to interop or we'll fail).  Go has the advantage of having Google's muscle behind it, so "rewrite the world" will not automatically fail, but it's an interesting difference, for sure.