Comment 13 for bug 1005075

I've reveiwed the diff, and this seems seems reasonable.

My concern is that this might change ABI - there are new fields added to the end of some classes, and some protected: functions have changed signature. I'm not familiar enough with the rules of C++ ABI to be confident this is safe; if you can get evidence to that effect (such as diffing the exported symbols) then I'll be happy with this.