title: Clang warning, -Wimplicit-fallthrough, not triggering for most of my files in Xcode
body: <p>When I add this warning under "Other C Flags" in xcodeproj file and build, the warning will only trigger in one of my files. I suspect it is because it is an Objective-C++ file, and the other ones I've tried to trigger this warning in are not. I added -Weverything to "Other C Flags" and it causes lots of warnings to pop up.</p>