Objective-C SDK modernization. When modernizing to
use NS_ENUM/NS_OPTIONS macros, add an import of
Foundation.h (or its module) as necessary.
rdar://18498550


git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@219225 91177308-0d34-0410-b5e6-96231b3b80d8