Provide a stable ABI python3.dll

[lazka]

See https://docs.python.org/3/c-api/stable.html#stable-application-binary-interface

This is currently handled here: https://github.com/python/cpython/blob/main/PC/python3dll.c

which I'm not sure how to translate to a mingw-w64 toolchain.

[Biswa96]

What would you like to use to translate that to a mingw-w64 toolchain - a DEF file, dllexport attribute or with other compiler/linker flag?

[lazka]

It looks like we might be able to do it with inline assembly:

// python3dll.c
 asm (".section .drectve\n\t.ascii \" -export:_Py_EllipsisObject=\\\"python3.11.dll._Py_EllipsisObject\\\" ,DATA\"");

$ gcc -shared -o python3.dll python3dll.c -Wl,--out-implib,libpython3.dll.a