@convexer it depends on the roadmap and target audience. Rust-in-Linux is an attractive target because everyone already uses Linux and they can get Rust into everything by making their play there. But it's an uphill battle and I think it's overall a bad idea; I blogged about this before and my opinions have been refined a bit since (more thought + watching how it's developed).
Making a new OS which is Linux-compatible would be much, much easier and faster.