Possiblity to pass custom argument to setup.py when installing a package.

[mgreive]

What's the problem this feature will solve?

It used to be possible to pass custom options with pip install that could be accesed in setup.py as described for example in this stackoverflow post. Since --install-options is now deprectated ( #11358) this is not possible anymore.

Describe the solution you'd like

I would like something similar to what used to be possible. Makeing a custom option accesable in setup.py. And if this should already exist maybe some documentation regarding that.
This is for example useful for projects with multiple versions to distribute. Especially if the wanted version needs to be known during the building process and can not be specified at run time.

Alternative Solutions

A workaround to my specific problem is using enviromental variables as suggested in the stack overflow post linked above. This is of course not very pretty and may be difficult for some people since it makes the install process more complicated.

Additional context

I posted a question regarding this on stackoverflow but I am starting to wonder if it is possible to get the result I want with --config-settings. If this should be the case it maybe would be nice to add some form of documentation explaining the use of --config-settings.

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[uranusjr]

--config-settings is tool-specific, and you should reach out to setuptools for how it can be used instead.