Folks,
Mozilla officially builds on MinGW: http://www.mozilla.org/build/win32.html#ss2.2
Bug #134113 tracking this effort was closed: http://bugzilla.mozilla.org/show_bug.cgi?id=134113
Unfortunately, the new windres I was working on did not make it in time for this release, so a bunch of ugly hacks had to be checked in to work around various problems, but hopefully we'll be able to remove them in a few weeks, when the next binutils package is released.
We can now start looking into the real Winelib port. :)