* util/grub-mkconfig.in: Stop setting GRUB_VIDEO_BACKEND. Make it

available as a user override instead.  Replace the gfxterm backend
check with a check that ${GRUB_PREFIX}/video.lst is non-empty.
* util/grub.d/00_header.in (load_video): New generated function.
Call it before loading gfxterm rather than loading
${GRUB_VIDEO_BACKEND}.
* util/grub.d/10_linux.in (linux_entry): Call load_video.
* util/grub.d/30_os-prober.in (osx_entry): Likewise.
* docs/grub.texi (Simple configuration): Document
GRUB_VIDEO_BACKEND.

util/grub.d/30_os-prober.in

@@ -44,7 +44,7 @@ EOF
 	save_default_entry | sed -e "s/^/\t/"
 	prepare_grub_to_access_device ${DEVICE} | sed -e "s/^/\t/"
 	cat << EOF
-        insmod ${GRUB_VIDEO_BACKEND}
+        load_video
         set do_resume=0
         if [ /var/vm/sleepimage -nt10 / ]; then
            if xnu_resume /var/vm/sleepimage; then