MAINT: Deduplication with abstract class

[marload]

config_cc and config_fc inherit abstract class config.

[mattip]

CI is failing: TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases. You might want to run python setup.py build_ext locally before resubmitting.

[mattip]

While distutils uses lower-case classes, I think we should use Upper-case. This will require more changes through the file ...

Suggested change

	class config(Command, metaclass=abc.ABC):
	class Config(Command, metaclass=abc.ABC):

[eric-wieser]

It's probably simplest to avoid using ABC here to avoid the conflict. At any rate, those methods are hooks for the base class, so not our concern to mark abstract.

[InessaPawson]

@marload Thank you for working on this! Do you think you could finish the PR some time soon?

[rossbar]

numpy.distutils has been officially deprecated, so it's probably worth revisiting whether this change should be considered at all.

[InessaPawson]

@rossbar Sebastian (@seberg) reached out to me with a similar comment. I'll close the PR.