Add a debug version of python

[nikhilweee]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

Background

There have been multiple conversations around supporting a debug build of python both in this repository (#73) and elsewhere (conda-forge/staged-recipes#4812). There have also been previous attempts at this (#86) but there hasn't been any progress in the last 6 years. This PR is an attempt to revive those efforts.

Details

I am fairly new to writing recipes for conda-forge. In fact, I have never written recipes before, so please be humble with all the help you can. What I propose is to have another output, python-debug, which passes the env vars PY_INTERP_DEBUG=yes and DEBUG_PY=yes. The build script build_base.sh is already equipped to handle these env vars and pass on --with-pydebug to the build process.

Benefits

• With this PR, users should be able to conda install python-debug to use a debug version of python.

Concerns

• Adding an additional output requires more CI resources, something that we might want to conserve.
• Adding another output makes meta.yaml even more messier.

Any feedback is much appreciated.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[nikhilweee]

@conda-forge-admin, please rerender

[nikhilweee]

I had initially thought of adding another output. But this had issues because conda doesn't create a separate build folder for each output (or maybe there is a way, I don't know yet). Now the approach is to have a separate output python-debug which only builds the debug version. Continuing in #597