gh-131238: Remove pycore_runtime.h from pycore_pystate.h

[vstinner]

• Remove includes from pycore_pystate.h:

  • pycore_runtime_structs.h
  • pycore_runtime.h
  • pycore_tstate.h
  • pycore_interp.h

• Reorganize internal headers. Move _gc_thread_state from pycore_interp_structs.h to pycore_tstate.h.

• Add 3 new header files to PCbuild/pythoncore.vcxproj

• Issue: Our internal headers are far too interlinked #131238

[vstinner]

I wrote two PRs to prepare this one:

• gh-131238: Add explicit include to pycore headers #131257
• gh-131238: Convert pycore_pystate.h static inline to functions #131352

[markshannon]

@vstinner why are you doing this right now? If it is so urgent, why did you not do it earlier?

This is creating a lot of churn and merge conflicts for my efforts to sort out the header files ##131351
which I need to fix actual issues around immortality #125174

[vstinner]

@vstinner why are you doing this right now? If it is so urgent, why did you not do it earlier?

Hi, I always wanted to reorganize pycore headers mess, and your issue was a good motivation to work on it. I waited until you merged your PR before pushing my changes. I didn't know that you have further changes in the queue. I will stop for now until you're done to avoid further conflicts.

[markshannon]

Hi, I always wanted to reorganize pycore headers mess, and your issue was a good motivation to work on it.

Glad to be a motivation 🙂

I waited until you merged your PR before pushing my changes. I didn't know that you have further changes in the queue. I will stop for now until you're done to avoid further conflicts.

Thanks. I'll let you know I'm done.