egl-headless: cursor_dmabuf: handle NULL cursor

The cursor dmabuf can be NULL, in case no cursor defined by the guest.
Happens for example when linux guests show the framebuffer console.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20180220110433.20353-3-kraxel@redhat.com
1 file changed