https://bugs.winehq.org/show_bug.cgi?id=42474
--- Comment #19 from Nikolay Sivov bunglehead@gmail.com --- (In reply to Sebastian Ernst from comment #16)
My understanding is that Wine even if it is set to Windows Vista or 7 returns an address for PathCchCombineEx which does not allow Python to fall back to PathCombineW. If PathCchCombineEx just was not there (in Windows Vista and 7 settings) or would return E_NOTIMPL, it might allow Python 3.6 to work (assuming a working implementation of PathCombineW).
Right, from their code, as soon as export is available it will be used, there's no Windows version thing, which is a good thing. Stub won't help here obviously, this needs real implementation in kernelbase.dll.