GH-131296: fix clang-cl warning on Windows in pegen.h

[chris-eibl]

Fix warning : fastcall calling convention is not supported on variadic function [-Wignored-attributes].
This warning is seen 7 times in a row: https://github.com/python/cpython/actions/runs/14006628024/job/39221297660#step:4:239

For 32bit builds of pythoncore, we'd see this another 7 times (and in case of PGO we'd triple up to 21 warnings).

MSVC seems to silently ignore it https://devblogs.microsoft.com/oldnewthing/20131128-00/?p=2543.

• Issue: clang-cl issues many warnings when building on Windows #131296

[chris-eibl]

cpython/Include/pyport.h

Lines 190 to 197 in 18249d9

	#if defined(_MSC_VER)
	/* ignore warnings if the compiler decides not to inline a function */
	# pragma warning(disable: 4710)
	/* fastest possible local call under MSVC */
	# definePy_LOCAL(type) static type __fastcall
	# definePy_LOCAL_INLINE(type) static __inline type __fastcall
	#else
	# definePy_LOCAL(type) static type

__fastcall is anyway only in effect for 32bit builds. The warning stems from the _freeze_module, which is by default compiled in 32bit mode (unless you override PreferredToolArchitecture). Let's simply convert to static inline.

[chris-eibl]

I think this is a skip news?

[vstinner]

LGTM. I agree with @chris-eibl's rationale that __fastcall is useless on this function.

[pablogsal]

LGTM Thanks a lot for the fix @chris-eibl