* Makefile.in (UNICODE_ARROWS, UNICODE_LINES): New variables (they
define the codes for arrows and lines used for the menu).
(ascii.pff): Generate fonts for $(UNICODE_ARROWS) and $(UNICODE_LINES)
as well.
* util/update-grub_lib.in (font_path): Prefer ascii.pff over complete
fonts, because the latter are too slow.