Well, Growl didn’t make a4 after all. It turns out that we were crashing in static builds if Growl was installed. It was determined that compiling statically was dropping code needed from within the Growl code, causing our crash.
It was a sad day, but the good news is that I have at least one fix! I’m about to attach it to Bug 378785, which is the bug opened for the crashes in the first place. It makes the nsIAlertsService code and the Growl code into dynamic libraries. We (Colin and myself) would like to get it working with static nsIAlertsService code and dynamic Growl code. It should make it into a5!