[PATCH] Fix for nasty LTO issue that's most obvious in ObjectiveC.

[Kevin Frei]

The reason I wasn't sure which was correct is because isExternallyIntialized is a default ctor parameter, so if someone's specifying a different value, then calling the copyAttributesFrom to fill in everything else, it's a bug. From a design perspective, having an API like copyAttributesFrom for a type with a ctor that has default parameters seems incredibly confusing. Perhaps I should eliminate the default parameter? And maybe this discussion should move over to llvmdev?

http://reviews.llvm.org/D6145