mkisofs is used, if mkhybrid do as we always have, if mkisofs add
args: -hfs-bless $n/install/powermac. note this *REQUIRES* the
mkisofs from woody, potato's will not work.
don't make HFS images for CDs > 1, its not needed.
I will have someone test this to ensure it works asap.
first CD where possible. We then make 2 copies of this, one with
non-US and one without. Useful for people wanting to create non-US and
US-safe CD sets without having to spend so much disk space.
Side-effects: The CD tress are now $(DIR)/CD<foo> instead of
$(DIR)/<foo>