The working principle is similar as before with x86, but instead of outputting .asm, it outputs .wat. This can be compiled into .wasm by using the wat2wasm assembler.
The header files are automatically generated during build. No need to #define anything; everything is fixed by the .asm file. This adds go as a dependency to run the unit tests, but this is probably not a bad thing, as go is probably needed anyway if one wants to actually start developing Sointu.