PEP 660 and setuptools

[pf_moore (Paul Moore)]

@pf_moore

OK, so what I’ll do is:

1. pip will collect config_settings as with any other option (including the possibility of per-requirement overrides from a requirements file).
2. pip will supply the config settings to every backend hook call.
3. I’ll dump the problem of handling this behaviour on backends I did a quick check of the flit and poetry source code, and both seem to ignore the config_settings parameter altogether, so I don’t believe they will have a problem here. Hopefully, the same will be true of other backends.

OK, the PR for this has just landed in pip, and should be in the next release. Have fun with it