Fix for LWG2454: Add raw_storage_iterator::base() member

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@236948 91177308-0d34-0410-b5e6-96231b3b80d8

include/memory

@@ -1855,6 +1855,9 @@ public:
     _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator++() {++__x_; return *this;}
     _LIBCPP_INLINE_VISIBILITY raw_storage_iterator  operator++(int)
         {raw_storage_iterator __t(*this); ++__x_; return __t;}
+#if _LIBCPP_STD_VER >= 14
+    _LIBCPP_INLINE_VISIBILITY _OutputIterator base() const { return __x_; } 
+#endif
 };
 
 template <class _Tp>