[mypyc] Fix wheel build for cp313-win

[cdce8p]

#17929 seems to have broken the wheel builder but only on Windows with Python 3.13.

  C:\Users\runneradmin\AppData\Local\pypa\cibuildwheel\Cache\nuget-cpython\python.3.13.0\tools\include\internal\pycore_unicodeobject.h(262): error C2375: '_PyUnicode_Equal': redefinition; different linkage
  D:\a\mypy_mypyc-wheels\mypy_mypyc-wheels\mypy\mypyc\lib-rt\pythoncapi_compat.h(1540): note: see declaration of '_PyUnicode_Equal'

  C:\Users\runneradmin\AppData\Local\pypa\cibuildwheel\Cache\nuget-cpython\python.3.13.0\tools\include\internal\pycore_pyhash.h(24): error C2375: '_Py_HashBytes': redefinition; different linkage
  D:\a\mypy_mypyc-wheels\mypy_mypyc-wheels\mypy\mypyc\lib-rt\pythoncapi_compat.h(1567): note: see declaration of '_Py_HashBytes'

https://github.com/mypyc/mypy_mypyc-wheels/actions/runs/11327195039/job/31497783023#step:4:3766

MSVC seems to require that the signature matches the upstream one exactly.

[JukkaL]

Thanks for the quick fix!

[cdce8p]

Opened python/pythoncapi-compat#115 to fix it upstream as well.