Luke,
Please please! Don't make me say what I did not say. I just said "I disagree", without any bad word. This may have been a bit terse, but I don't consider the issue tracker as a place to express one's feelings; hey, other core developers could have written "-1" instead.
I'm not trying to block this development, on the contrary, I'm getting interested in it so that we can merge it into CPython development tree. I'm here to help. Really.

I did try to port python to the mingw32 compiler some years ago, and in the proposed patch I retrieve some of the changes I did at the time.  IIRC I gave up because there were issues with the localtime function, and because of differences in the sprintf format. I'm glad that you found how to solve them.
FYI, I'm also the maintainer of pypy on Windows, and we support both MSVC (8, 9, 10) and mingw32.

> i encountered dozens of assumptions that "if sys.platform == 'win32'
> then you MUST be building using visual studio: f*** off with your
> attempt to compile this module using gcc".

There are not so many of them in distutils. Did you see them in third-party packages?
Code like this is wrong and should be changed, just like "#ifdef MS_WINDOWS" (=the platform) is not equivalent to "#ifdef _MSC_VER" (=the compiler)