Handle "typeof" in Objective-C format string checking.  This previously crashed.

Yes, this came from actual code.

Fixes <rdar://problem/13557053>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179155 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed