Here's an ugly hacked up version of Pythons 'with' statement:
https://gist.github.com/nlyan/7319c7b2a6328460ce9c
As for external libraries...sometimes it requires a bit of ingenuity to find that perfect 'wrap everything!' vs 'write C' balance... but it's usually not so bad if you approach the problem judiciously. unique_ptr and shared_ptr's capabilities are often underestimated in this regard for instance. Both can be used with external reference counting, the former being the most efficient.
> Simple rule: a class should never contain handles or pointers to more than a single resource. Composition handles the rest.
The issue with this is that in the real world, you have to deal with 3rd party libraries and frameworks or even the OS syscall interface which don't follow this guideline. So you'll end up writing wrappers for all your "foreign" objects from any other libraries you use. This is a lot of work and creates impedance mismatch problems when there's no simple clearly established concept of ownership (e.g. the wrapped objects are already reference counted) or the assumptions of the library aren't friendly to C++ style semantics.
If you live in a "modern C++ only" bubble, this isn't an issue.