EGL: Add support for eglQueryDisplayAttribKHR and NV.
!239 (merged) adds support for adding new EGLDeviceEXT handles, and adds handling so that eglQueryDisplayAttribEXT(EGL_DEVICE_EXT)
will update libglvnd's (device -> vendor) mapping.
But, I forgot to also add support for eglQueryDisplayAttribKHR
and eglQueryDisplayAttribNV
. So, this change adds the other two suffixes.
That includes both handling the EGL_DEVICE_EXT
attribute for all three, and handling a vendor library that doesn't support the EXT version.