gh-85283: _stat extension now uses the limited C API

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The _stat C extension is now built with the limited C API.

• Issue: [C API] Convert a few stdlib extensions to the limited C API (PEP 384) #85283

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📚 Documentation preview 📚: https://cpython-previews--110711.org.readthedocs.build/

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• Discussion: https://discuss.python.org/t/use-the-limited-c-api-for-some-of-our-stdlib-c-extensions/32465
• Previous attempt at the end of August: PR gh-85283: _stat extension uses the limited C API #108573

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cc @erlend-aasland @corona10 @encukou

[gpshead]

I approved as this seems trivial so "lets do it!", obviously figuring out the windows build excitement in CI needs to happen first.

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What's going on? Now Windows build fails with:

LINK : fatal error LNK1104: cannot open file 'python313_d.lib' [D:\a\cpython\cpython\PCbuild\pythoncore.vcxproj]

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LINK : fatal error LNK1104: cannot open file 'python313_d.lib' [D:\a\cpython\cpython\PCbuild\pythoncore.vcxproj]

Ok, I found the root issue and wrote a fix: PR gh-110725. The problem comes from PyAPI_FUNC(), PyAPI_DATA() and PyMODINIT_FUNC macros which have a different implementation depending if the 3 Py_BUILD_CORE macros are defined or not.

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Merged, thanks for the review @gpshead and @erlend-aasland.