In case anyone’s interested, here are Firefox 3.5 compatible xpi builds for Windows i386 (compiled on Visual Studio 2008 SP1) and Linux i386 and x86_64 (compiled using gcc 4.3.3 on Ubuntu using my patch posted above):

http://gkovacs.xvm.mit.edu/google-gears/gears-win32-opt-0.5.25.0.xpi

http://gkovacs.xvm.mit.edu/google-gears/gears-linux-0.5.25.0.xpi

http://gkovacs.xvm.mit.edu/google-gears/gears-linux-x86_64-0.5.25.0.xpi

via Issue 749 – gears – Gears 0.4.20.0 not compatable with Firefox 3.1 Beta 1 – Google Code.