Also lock/unlock the module only on creation/destruction of the object.

That can only happen by manually modifying
select_vertex_implementation() and select_fragment_implementation(),
which may be useful for testing non-default vertex / fragment pipeline
implementations.

In some cases, WM's will modify the _NET_WM_STATE of our own windows.
Most notably, this can happen when the WM maximizes our window, but
mutter has been known to alter the fullscreen state as well. If we
want to reconfigure our window later, we'll probably have to remove
these states, which means we need to remember that they were set.

Also lock/unlock the module only on creation/destruction of the object.

Also lock/unlock the module only on creation/destruction of the object.