[Gtkradiant] New Radiant build fixes q3map2 crash on Windows

[Nerius Landys]

http://porky.nerius.com/radiant-windows-builds/ZeroRadiant_Win_2011-04-05.zip

This is a build from the latest stuff in SVN.

There was a bug where q3map2 was running out of stack space on
Windows.  I think the default stack size on Windows is 1 MB.  I bumped
it up to 8 MB.

I will be fixing more critical bugs but not at a terribly fast pace.
I fixed this q3map2 crash because obviously it was critical since
nobody on Windows was able to compile a map with patch mesh.