pyproject build requires build-system definition

[mweinelt]

A pyproject.toml file is only useful for building a python project, when it has a build-system section and a build-backend defined.

❌ https://github.com/dfunckt/django-rules/blob/master/pyproject.toml
✔️ https://github.com/pyca/cryptography/blob/main/pyproject.toml#L1-L10

Don't offer it, when the section does not exist.

[figsoda]

https://pip.pypa.io/en/stable/reference/build-system/pyproject-toml/#fallback-behaviour

Perhaps it should just recommend setuptools over pyproject if it is absent?

[mweinelt]

Apparently you can just use pyproject format if no build-system is present, but either setup.cfg or setup.py are. In either case you then need setuptools in nativeBuildInputs.

[figsoda]

In either case you then need setuptools in nativeBuildInputs.

fixed in 22e325b