Fix LWG#2127: Move-construction with raw_storage_iterator.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@251247 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/memory b/include/memory
index 4ed3308..97ad440 100644
--- a/include/memory
+++ b/include/memory
@@ -1909,6 +1909,10 @@
     _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator*() {return *this;}
     _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator=(const _Tp& __element)
         {::new(&*__x_) _Tp(__element); return *this;}
+#if _LIBCPP_STD_VER >= 14
+    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator=(_Tp&& __element)
+        {::new(&*__x_) _Tp(_VSTD::move(__element)); return *this;}
+#endif
     _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;}