Getting rust-embedded/cross running on macOS

One of the great promises and benefits of Rust is that you can easily write code that cross-compiles to various different targets. Not only that but the ecosystem is constantly evolving and trying to make this process as painless as possible. Rustup makes managing different target toolchains a breeze. However, if you don't want to pollute your environment with all the different dependencies of those target toolchains you can try cross.

Simply put cross uses Docker containers to build your project. It mimics cargo's CLI arguments as much as possible but instead of using the rustup toolchains for a given target it spins up a Docker container. It then builds your project in it and spins down the container. To put it even simpler - it's great!

Initially, I had missed one important disclaimer. I got super confused when it wasn't working on macOS. As of this writing, the current version of cross (0.1.14) is only working for Linux hosts. On macOS, it will just act as a proxy and let cargo do its usual build process with a different --target argument.

Over the last couple of years, Docker support for macOS has been getting more solid. The kind people of the Rust Tools team have actually made cross work with macOS but just haven't gotten around to making a release yet.

The solution until the next release is simple. Instead of doing

cargo install cross

Just do

cargo install --git