The main advantage of switching to glad from glLoadGen is that, apart
from being actively maintained, it supports a customizable entrypoint
loader function, which makes it possible to also support OpenGL ES.
If an OpenGL object is created, bound to a binding using the state
tracker, and then destroyed, a newly created object can be assigned the
same numeric handle by OpenGL. However, even though it is a new object,
and thus needs to be bound to the binding again, the state tracker
compared the current and previous handles and concluded that no change
needed to be made, leading to failure to bind objects in certain cases.
This manifested as broken text in VVVVVV, which this commit fixes along
with similar texturing problems in other games.
