Clang and linux portability fixes#10

KatashiMonosato wants to merge 3 commits intoswiftlang:masterswiftlang/swift-corelibs-libdispatch:masterfrom

KatashiMonosato:clang-and-linux-portability-fixesKatashiMonosato/swift-corelibs-libdispatch:clang-and-linux-portability-fixesCopy head branch name to clipboard