Wrapping a whole library is boilerplate, ineffective, and wrong in most cases. It can be done in a much clever way. I'd say that wrapping a library is appropriate mostly in case of UI component libraries, and again, you have to be adding some additional core functionality of yours to all the components for this to be needed.
- if too much modifications and additions are needed, this is most likely not the library you are looking for
- if there is a moderate amount of additions and modifications - there are always the design patterns that come handy in those cases. The Decorator pattern (allows new/additional behaviour to be added to an existing object dynamically) , for example, is rather suitable for the most cases.
- IDE search/replace and refactoring capabilities offer an easy way to change your code in all required places if some important change is needed and a wrapping object appears. (of course, unit-tests would be helpful here ;) )
