If I remember correctly from this and last years WWDC, large parts (if not all by now) of iOS and OS X Lion are built with Clang/LLVM and have been for some tim

If I remember correctly from this and last years WWDC, large parts (if not all by now) of iOS and OS X Lion are built with Clang/LLVM and have been for some time. I'd say Clang's been ready for a while!