The private PyCode and PyOptimizer APIs use "unnamed structs/unions" which are not allowed in ISO C99: see #120293.

I propose to move private PyCode and PyOptimizer APIs to the internal C API.

6 PyUnstable optimizer functions are moved to the internal C API:

• PyUnstable_Replace_Executor()
• PyUnstable_SetOptimizer()
• PyUnstable_GetOptimizer()
• PyUnstable_GetExecutor()
• PyUnstable_Optimizer_NewCounter()
• PyUnstable_Optimizer_NewUOpOptimizer()

Linked PRs

• gh-120642: Move private PyCode APIs to the internal C API #120643
• [3.13] gh-120642: Move private PyCode APIs to the internal C API (#120643) #121043
• gh-120642: Move _PyCode_CODE() to the internal C API #121644
• [3.13] gh-120642: Move _PyCode_CODE() to the internal C API (GH-121644) #121729