Add friends __count_bool_true and __count_bool_false to __bit_iterator.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@156543 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__bit_reference b/include/__bit_reference
index bc34555..95a1007 100644
--- a/include/__bit_reference
+++ b/include/__bit_reference
@@ -1242,6 +1242,10 @@
                                                                           typename _Dp::size_type);
     template <class _Dp> friend __bit_iterator<_Dp, false> __find_bool_false(__bit_iterator<_Dp, false>,
                                                                            typename _Dp::size_type);
+    template <class _Dp> friend typename __bit_iterator<_Dp, false>::difference_type
+                   __count_bool_true(__bit_iterator<_Dp, false>, typename _Dp::size_type);
+    template <class _Dp> friend typename __bit_iterator<_Dp, false>::difference_type
+                   __count_bool_false(__bit_iterator<_Dp, false>, typename _Dp::size_type);
 };
 
 _LIBCPP_END_NAMESPACE_STD