I'm working towards getting libadns lastrited. Since wireshark supports both libadns and c-ares, it shouldn't be a problem to remove libadns support.
USE=libadns is masked in profiles/base/package.use.mask. I have added new ebuilds for the stable branches and adapted 1.12.0_rc2 in place.
Please leave this bug open so that we know when to clean up the base profile.
No wireshark ebuilds depend on net-libs/adns any longer.