In addition, WebRTC's new screen capture code doesn't compile at all on 10.4. I think I have it hacked so that it will work without it and we can still use WebRTC for webcams as we are doing now, but it's all very rickety. The rapid development of that code means further bustage in the near future.
Overall, although it works, I'm not happy with what I had to do to make it work. I'm not sure I'm going to make a release of 33 (other than changesets) -- I might turn this around immediately into aurora 34 and try to get cracking on converting the MIPS IonMonkey JIT because if the stack limitations of irregexp become a big problem, I may need the rest of the Ion JIT to overcome the performance hit we will take by disabling native regular expressions. I think this should be the biggest priority for 38, the next ESR. There may not be much further we can take the browser after that if we even get that far.