There are "," expressions in decltype(). Do not fail them when decltype is a macro.
Pull-request for branch users/somov/fix/libcxx_commas_in_decltype
@@ -878,7 +878,7 @@ template <unsigned> struct __static_assert_check {};
#ifdef _LIBCPP_HAS_NO_DECLTYPE
// GCC 4.6 provides __decltype in all standard modes.
#if __has_keyword(__decltype) || _LIBCPP_CLANG_VER >= 304 || _GNUC_VER >= 406
-# define decltype(__x) __decltype(__x)
+# define decltype(__x, ...) __decltype(__x, __VA_ARGS__)
#else
# define decltype(__x) __typeof__(__x)
#endif
