One-shot semantics in GHC event manager

[Kazu Yamamoto (=?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?=)]

> Ahh, yes. Sorry, I forgot you were on 7.8.  Just pushed a new patch to
> the event-rework-squashed branch [1].

I believe that you are trying to merge your patches to GHC 7.8.4?
If not, I will work on the GHC head branch.

--Kazu