mingw32 gcj (not yet)

[Tony Kimball]

Just so all mingw32-interested parties know:

I easily incorporated the patch from the archive, into my mid-July
snap of the 3.0 branch, and with good success.

I found that after around July 21, the 3.0 branch no longer supported
SJLJ exceptions, which I needed for mingw32 and cygwin, so I'm
hanging back in July.

I haven't been working on mingw32 gcj for a few days, but should
be trying to finish things up next week.