The attribute that's added in D58365 allows us to avoid making unreliable guesses on whether the current function is a MIG server routine.
Rebase due to an update in D58365 - namely, add support for Objective-C messages and blocks that are now allowed to wear the attribute.
Whoops - make sure that the Objective-C test does actually test something.
Ooh, I didn't know you could split RUN lines like this. That is awesome!
Committed as rC354638 but i screwed up the link in the commit message.