Add r180263 back, but fix hasBraces() to be correct during parsing.

Original commit message:

Fix a case in linkage computation that should check for single line extern "C".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180591 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed