> The toolchain is difficult to build, but the patch is easy to review, it
> just moves the MS_WIN64 outside the MS compiler specific part. If it
> does not break the MS toolchain (the one used to build the official
> python), I don't see the problem.

As a principle, I always try to reproduce a problem when reviewing a
patch. In many cases, doing so reveals insights into the actual problem,
and leads to a different patch.

That the patch is "harmless" is not a convincing reason to apply it.

> I can make the toolchain available to you as a tarball, though, so that
> you can easily test from a windows command shell without having to
> install anything.

That would be nice.