I have updated the Qt wiki on MinGW-w64:

It has a nice explanation (which was *wrong* on many accounts until now) of various "stuff".

I'm attempting to build the prereqs now, I might upload them when I succeed.

Also: it seems the Qt Project chose for "posix" threading for all the wrong reasons in their own release to public installers, and has no idea of the possible performance impact. It will be positive to get winpthreads and posix threading out in the wild though :-)