Objective-C rewriter. Use _WIN64 instead of __LLP64__
to conditinalize on 64bit length in a generated meta-data.
// rdar://16489050


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206402 91177308-0d34-0410-b5e6-96231b3b80d8