This EGL extension has been added in [1]. The upsides are:
- We directly get a render node, instead of having to convert the
primary node name to a render node name.
- If EGL_DRM_RENDER_NODE_FILE_EXT returns NULL, that means there is
no render node being used by the driver.
[1]: https://github.com/KhronosGroup/EGL-Registry/pull/127