Generate Cython code at build time

[yunline]

• Generate Cython code at build time.
• Remove cython option from setup.py. (but keep the cython_only)
• Add cython-generated files into .gitignore .
• Bump cython to 3.0.0 #2395

Reference:
pygame/pygame#2916
#1862

[MyreMylar]

I'm generally approving of this as a stop gap before steadily turning cython files to C files.

[pmp-p]

Though the wasm CI is already doing that, this is probably a bad idea for testing against python git where cython files may need to be edited.

This is what i do locally after 3.11 and 3.12(git) are built:

• i build with python3.11 : cython files + pygame
• Then if i know cython files will fail on 3.12, i patch the 3.11 generated one
• then continue build without running cython_only.

[yunline]

Though the wasm CI is already doing that, this is probably a bad idea for testing against python git where cython files may need to be edited.

Maybe we can solve this problem by adding a 'non-cython' option.

[MyreMylar]

slightly longer term (but getting closer) the plan is to clear out all the cython code entirely.

Is this PR useful enough to current cython development to get over the downsides? Or should we close it. I tend to avoid cython entirely.

[dr0id]

Why are those lines not in the build command? Or are these files needed elsewhere too?

[dr0id]

please add a description:
description = "short doc what this command does"

can be seen with: python setup.py --help-commands

there is also python setup.py cython_only --help
not sure what that would produce at the moment.

[yunline]

It seems other commands don't have descriptions too. Maybe we need another pr to fix that.

[dr0id]

yes, see #2360

[ankith26]

This PR has been superseded by #2831 because we recently introduced the new buildconfig, so I'm closing this

But thanks for starting the work on this!