Assume devkitARM ships with only a single version, so then find the
first entry matching `${DEVKITARM}/lib/gcc/arm-none-eabi/*/include` and add it
to the -isystem includes.
Effectively:
- Move the previous bindgen script into build.rs
- In lib.rs, include the file generated at build time
- Compile inline statics with devkitARM toolchain
- Remove now-unneeded reimplementations of inline statics
- Use doxygen_rs to clean up the docs of the generated bindings.
Nice! This cleans up the repo a lot and also ensures we are using the
canonical implementations of those inline functions, which should help
prevent mistakes as well.