I'm not sure what happened here, but this ebuild declares around 20 pkgs in RDEPEND, then immediately re-declares RDEPEND and wipes them all out. I noticed this when my cinnamon-session build failed with missing libcanberra, it did not attempt to pull it in as a dep. Also, the second declaration of RDEPEND has ${COMMON_DEPEND} which is not declared anywhere. Maybe the first RDEPEND= declaration was supposed to be COMMON_DEPEND= ? But what's the point anyway, COMMON_DEPEND is only used once, so it's not common.. Anyway, thanks for looking into this!
You are right, the first RDEPEND should have been COMMON_DEPEND - and same is true for the third RDEPEND. Thanks for reporting! + 13 May 2014; Alexandre Rostovtsev <tetromino@gentoo.org> + cinnamon-session-2.2.0.ebuild: + Fix COMMON_DEPEND (bug #510196, thanks to Ben Kohler).