just like the __call magic method we can use in PHP to hook a call to a non defined method, is there a way to hook a call to an undefined constant or variable?
Like A::B, where B doesn't exist.
No. Constants are evaluated at opcode compile time not runtime, so there's no way to 'catch' them. There is still an issue with php related to this where a parent class cannot call a childs constant inside a parents method.
You're probably looking for __get and __set. I'm not really sure how it works with static constants though, you might only be able to work with instanced objects. See G-Nugget's comment regarding using them statically.