Native bindings to the NV_context_priority_realtime extension.

This extension allows an EGLContext to be created with one extra priority level in addition to three priority levels that are part of EGL_IMG_context_priority extension.

This new level has extra privileges that are not available to other three levels. Some of the privileges may include:

• Allow realtime priority to only few contexts
• Allow realtime priority only to trusted applications
• Make sure realtime priority contexts are executed immediately
• Preempt any current context running on GPU on submission of commands for realtime context

The mechanism for determining which EGL context is allowed to use this priority level is platform dependent.

Requires IMG_context_priority.