Guile on MinGW

[Mike Gran]

Hello-
I guess this question is really for Eli.  I hope he's lurking.
So, I'm trying to put together the next release for the
Guile-ncurses bindings, and I want to drop 1.8.x compat. MinGW
seems to be stuck on Guile 1.8.8. 
But MinGW seems to be splitting into two camps, as far as I can
tell: mingw.org and mingw-w64.org.
If I wanted to test my upcoming release, which MinGW should
I using to compile guile-2.0.x and test my new release of
guile-ncurses?
Thanks,
Mike Gran