Index: llvm/trunk/lib/Support/Unix/Path.inc =================================================================== --- llvm/trunk/lib/Support/Unix/Path.inc +++ llvm/trunk/lib/Support/Unix/Path.inc @@ -1203,7 +1203,7 @@ /// implementation. std::error_code copy_file(const Twine &From, const Twine &To) { uint32_t Flag = COPYFILE_DATA; -#if __has_builtin(__builtin_available) +#if __has_builtin(__builtin_available) && defined(COPYFILE_CLONE) if (__builtin_available(macos 10.12, *)) { bool IsSymlink; if (std::error_code Error = is_symlink_file(From, IsSymlink))