Calibre switched to podofo dep from ver 5.14 (see changelogs), adding podofo dependancy (podofo ebuild at bug #140557 ) allows to remove pdftk dep (which means also gcj compiled with gcc). patch will follow. Reproducible: Always
Created attachment 196093 [details, diff] calibre-0.6_beta10-podofo.patch ebuild patch to use podofo dependancy (I choosed "tk" as USE flag but it may be choosed better )
Well, pdftk and tk are totally unrelated. So, I changed it to || ( app-text/podofo >=app-text/pdftk-1.12 ) in the 0.6_beta10 ebuild. Thanks for reporting.