support free-threading python

[vicentebolea]

This PR adds an option in make_relocatable_python_framework.py that allows supporting free-threading python dists.

This has been tested in the VTK upstream CI.

[vicentebolea]

@gregneagle these changes are needed to support free-threading python distributions.

[mathstuf]

FWIW, changes LGTM.

[gregneagle]

Hey, thanks for this. I don't actually use this tool any longer -- I wrote it many years ago to build the "embedded" Python framework for Munki: https://github.com/munki/munki
Munki has since been rewritten in Swift and no longer needs or includes a Python interpreter. So I think it's time for people and projects that use this tool to fork it, as I don't have the time or motivation to maintain it any longer, and certainly don't have the background or motivation to maintain it for "free-threading python distributions" (whatever those are!) :-)

[vicentebolea]

@gregneagle would you support Kitware supporting this tool in the form of a new fork? We need this for some of our core projects.

[gregneagle]

It's an open source project so of course you can fork it. I do know some other open source projects like AutoPkg and MacAdmins Python also rely on this, and it would be nice to have a soft landing place for them (instead of multiple forks).
Years ago I really tried hard to get the Python.org project to figure out how to build their Python framework so that relocatable-python didn't need to exist at all, but I failed.

[mathstuf]

Thanks; we'll reach out to them to see if they want to set up an org or agree on an org to host it between those of us still using it.