In order for samba to work with cups, it has to be compiled against cups and so will not run without libcups being present.
The idea was to separate out libcups, which is relatively small, from the cups extension, which is relatively large, so that a user would only need to load libcups in order for the samba extension to run.
As several printing systems (hplip, gutenprint, etc) seem to be able to work without foomatic-rip, I will remove foomatic-rip from the cups extension. Since foomatic-rip depended on perl5, this has the effect of removing the dependency on perl5.
I'm testing the new extensions - at the moment:
samba - deps libcups
cups - deps libcups, dbus, expat2