libstdc++: Add 'typename' for Clang compatibility

Clang doesn't yet implement the C++20 change that makes 'typename'
optional here.

libstdc++-v3/ChangeLog:

	* include/std/ranges (adjacent_transform_view::_Iterator): Add
	typename keyword before dependent qualified-id.

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index dad1e4c9f939cf6ec58c460b9e749bf1260de8d7..2b5cb0531f02c96c45eaddf41dbe4242d7d90915 100644 (file)
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -5555,7 +5555,7 @@ namespace views::__adaptor
       using __detail::__unarize;
       using _Res = invoke_result_t<__unarize<__maybe_const_t<_Const, _Fp>&, _Nm>,
                                   range_reference_t<_Base>>;
-      using _Cat = iterator_traits<iterator_t<_Base>>::iterator_category;
+      using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
       if constexpr (!is_lvalue_reference_v<_Res>)
        return input_iterator_tag{};
       else if constexpr (derived_from<_Cat, random_access_iterator_tag>)