It's not available in OpenGL ES and officially it's not supported on OpenGL 3.0/3.1.
Fallback to old depth range code if there is no method to disable depth clipping.
It's more important to have correct clipping than to have accurate depth values.
Inaccurate depth values can be fixed by slow depth.
Sorts out references that cause some modules to be kept around after
backend shutdown.
Should also solve the issue with errors being thrown due to the config
being loaded after device creation, leading to the incorrect device being
used in a multi-adapter system.