The glue is done using the [cxx crate](https://cxx.rs/) on the Rust
side.
As a proof-of-concept, only a small console command (`rust_version`)
printing the currently used Rust version was added.
You can generate and open the Rust documentation using
`DDNET_TEST_NO_LINK=1 cargo doc --open`.
You can run the Rust tests using `cmake --build <build dir> --target
run_rust_tests`, they're automatically included in the `run_tests`
target as well.
Rust tests don't work on Windows in debug mode on Windows because Rust
cannot currently link with the debug version of the C stdlib on Windows:
https://github.com/rust-lang/rust/issues/39016.
---
The stuff in `src/rust-bridge` is generated using
```
cxxbridge src/engine/shared/rust_version.rs --output src/rust-bridge/engine/shared/rust_version.cpp --output src/rust-bridge/engine/shared/rust_version.h
cxxbridge src/engine/console.rs --output src/rust-bridge/cpp/console.cpp --output src/rust-bridge/cpp/console.h
```
