Development docs

[CyberTailor]

I couldn't find any development docs for Meson (for e.g. adding new compilers). Do they exist?

[eli-schwartz]

The current state of affairs is that this more or less requires you to figure it out yourself or ask questions.

A good starting point would be looking at how #8706 handled this when adding cython support. Basically the mesonbuild/compilers/ subsystem needs to have detect.py find a compiler and also add a new implementation file $lang.py which provides the necessary interface. Then backend/backend.py / ninjabackend.py should produce build edges when that language is used.