Make OpenGL extensions available in bgl

It would be really helpful if we could use OpenGL extension functions from bgl. I'm trying to write a custom interactive RenderEngine using Vulkan, but for now everything must be drawn using OpenGL. Copying the entire frame to CPU and back doesn't seem very efficient, but luckily there is an OpenGL extension namd EXT_memory_objects that allows use to use Vulkan images from OpenGL. If we could use that extension from bgl, that would be great.