Do a lookup for the blocks runtime globals to see if they were declared,
instead of codegen waiting to consume such a declaration, which won't
happen if that decls are coming from a PCH.

Fixes rdar://10028656.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139359 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed