Add missing header (NFC)
Add missing header (NFC)

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@266597 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld