handle disabling match for std::vector differently

So that it actually works...

bindings/CXX11/adios2/cxx11/Engine.h

@@ -27,25 +27,22 @@ namespace detail
 template <class...>
 using void_t = void;
 
-}
+} // end namespace detail
 
 template <typename C, typename = void>
 struct ndarray_traits : std::false_type
 {
 };
 
-// disable considering std::vector ndarray-like since it causes ambiguity with
-// existing std::vector-based overloads
-template <typename T>
-struct ndarray_traits<std::vector<T>> : std::false_type
-{
-};
-
 template <typename C>
 struct ndarray_traits<
     C, detail::void_t<typename C::value_type, typename C::pointer,
                       typename C::size_type, decltype(std::declval<C>().data()),
-                      decltype(std::declval<C>().size())>> : std::true_type
+                      decltype(std::declval<C>().size()),
+                      // don't match std::vector since it's handled separately
+                      typename std::enable_if<!std::is_same<
+                          C, std::vector<typename C::value_type>>::type>>>
+: std::true_type
 {
     using value_type = typename C::value_type;
     using pointer = typename C::pointer;