libstdc++: Add 'typename' to fix compilation with Clang

	* include/bits/ranges_algo.h (shift_right): Add 'typename' to
	dependent type.

libstdc++-v3/ChangeLog

+2020-03-02  Jonathan Wakely  <jwakely@redhat.com>
+
+	* include/bits/ranges_algo.h (shift_right): Add 'typename' to
+	dependent type.
+
 2020-03-01  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/abi/post/x86_64-linux-gnu/x32/baseline_symbols.txt: Updated.

libstdc++-v3/include/bits/ranges_algo.h

@@ -3710,7 +3710,7 @@ namespace ranges
       if (__n == 0)
 	return __first;
 
-      using _Cat = iterator_traits<ForwardIterator>::iterator_category;
+      using _Cat = typename iterator_traits<ForwardIterator>::iterator_category;
       if constexpr (derived_from<_Cat, bidirectional_iterator_tag>)
 	{
 	  auto __mid = ranges::next(__last, -__n, __first);