The ebuilds for cups-pdf are missing a dependency to ghostscript, but without it its hard to generate pdfs ;) Here are patches for the 2 ebuilds. I used a simple depend to ghostscript since I couldn't find out on which version it depends.
Created attachment 19204 [details, diff] diff -u cups-pdf-1.0.ebuild
Created attachment 19205 [details, diff] diff -u cups-pdf-1.1.ebuild
thx, fixed :)