Comment 3 for bug 136962

Here's an updated debdiff:

Review points:
1) postinst now checks for the existence of $unud, and does nothing if it doesn't exist. It didn't seem important enough to add a dependency on update-notifier | adept-notifier
2) $unud is actually defined in postinst (stupid ctrl-k!)
3) It seems the consensus of #ubuntu-motu is that the notifications should be for high-priority notifications only.
4) Although it's possible someone will want to call Xgl-session themselves, it's unlikely. It's been moved to /usr/share/xserver-xgl, as suggested.