Other packages (e.g., audacious-3.2) make the dependency optional, why not lxpolkit?
It's a bug in the audacious ebuild then. Let's not repeat the mistake. GTK+-3 is an upgrade over GTK+-2 and there is absolutely no reason for lxpolkit to have GTK+-2 available anymore. *** This bug has been marked as a duplicate of bug 374057 ***