Share the splash screen from isolinux in grub

This adds the version information on the grub splash screen and offers
the image at 800x600 instead of 640x480, which looks less unsharp.

scripts/build/binary_syslinux

@@ -311,11 +311,14 @@ then
 			cp "${_TARGET}/splash.svg" chroot
 			Chroot chroot "rsvg-convert --format png --height 480 --width 640 splash.svg -o splash.png"
 			mv chroot/splash.png "${_TARGET}"
+			Chroot chroot "rsvg-convert --format png --height 600 --width 800 splash.svg -o splash800x600.png"
+			mv chroot/splash800x600.png "${_TARGET}"
 			rm -f chroot/splash.svg
 			;;
 
 		false)
 			rsvg-convert --format png --height 480 --width 640 "${_TARGET}/splash.svg" -o "${_TARGET}/splash.png"
+			rsvg-convert --format png --height 600 --width 800 "${_TARGET}/splash.svg" -o "${_TARGET}/splash800x600.png"
 			;;
 	esac
 fi
@@ -323,7 +326,7 @@ rm -f "${_TARGET}/splash.svg"
 
 # Tweak the grub theme to reuse the syslinux background image if grub doesn't have its own
 if [ -e binary/boot/grub/live-theme/theme.txt ] && [ ! -e binary/boot/grub/splash.png ]; then
-	sed -i -e 's|^desktop-image:.*|desktop-image: "/isolinux/splash.png"|' \
+	sed -i -e 's|^desktop-image:.*|desktop-image: "/isolinux/splash800x600.png"|' \
 	-e 's|^title-text:.*|title-text: ""|' \
 	binary/boot/grub/live-theme/theme.txt
 fi