Use __rebind_pointer to avoid #ifdef block

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@256654 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/unordered_map b/include/unordered_map
index 3c774d4..85a54a7 100644
--- a/include/unordered_map
+++ b/include/unordered_map
@@ -656,7 +656,6 @@
 {
     _HashIterator __i_;
 
-    typedef pointer_traits<typename _HashIterator::pointer>      __pointer_traits;
     typedef const typename _HashIterator::value_type::value_type::first_type key_type;
     typedef typename _HashIterator::value_type::value_type::second_type      mapped_type;
 public:
@@ -664,13 +663,8 @@
     typedef pair<key_type, mapped_type>                          value_type;
     typedef typename _HashIterator::difference_type              difference_type;
     typedef value_type&                                          reference;
-    typedef typename __pointer_traits::template
-#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
-            rebind<value_type>
-#else
-            rebind<value_type>::other
-#endif
-                                                                 pointer;
+    typedef typename __rebind_pointer<typename _HashIterator::pointer, value_type>::type
+        pointer;
 
     _LIBCPP_INLINE_VISIBILITY
     __hash_map_iterator() _NOEXCEPT {}
@@ -712,7 +706,6 @@
 {
     _HashIterator __i_;
 
-    typedef pointer_traits<typename _HashIterator::pointer>      __pointer_traits;
     typedef const typename _HashIterator::value_type::value_type::first_type key_type;
     typedef typename _HashIterator::value_type::value_type::second_type      mapped_type;
 public:
@@ -720,13 +713,8 @@
     typedef pair<key_type, mapped_type>                          value_type;
     typedef typename _HashIterator::difference_type              difference_type;
     typedef const value_type&                                    reference;
-    typedef typename __pointer_traits::template
-#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
-            rebind<const value_type>
-#else
-            rebind<const value_type>::other
-#endif
-                                                                 pointer;
+    typedef typename __rebind_pointer<typename _HashIterator::pointer, const value_type>::type
+        pointer;
 
     _LIBCPP_INLINE_VISIBILITY
     __hash_map_const_iterator() _NOEXCEPT {}