Fixing sphinx build due to diagnostic:
Fixing sphinx build due to diagnostic:

/opt/llvm/build.attributes.src/tools/clang/docs/CommandGuide/clang.rst:338: WARNING: unknown option: -flto=full

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@282148 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang