Fix PR10510: http://llvm.org/bugs/show_bug.cgi?id=10510

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136232 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/type_traits b/include/type_traits
index ec12b6b..be893b0 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -3014,11 +3014,15 @@
 
 template <class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
 typename enable_if
 <
     is_move_constructible<_Tp>::value &&
     is_move_assignable<_Tp>::value
 >::type
+#else
+void
+#endif
 swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
                                     is_nothrow_move_assignable<_Tp>::value)
 {