cups provide a php extension (when it founds php). It would be better to handle that manually with a use flag. I think I don't have to mention why it's much better to have a php use flag. reproduced in 1.2.1-r2 (I think, I just updated) and 1.2.2.
want to contribute an ebuild patch? :)
thanks, I added the flag in cups 1.2.3