Portage is complaining about this every time an operation is made: Invalid USE flag in '/usr/portage/profiles/base/use.mask': 'net-libs/ortp zrtp' Seems the cause is the zrtp flag being removed along with older versions of ortp. I think we should either restore the USE or even better remove the mask.
Michał, since the mask is signed by you I'm assigning you the bug and CCing Tony as package maintainer. Mask is provided below for further reference. # Michał Górny <mgorny@gentoo.org> (15 Sep 2014) # Unsuccessful version bump of net-libs/libzrtpcpp, seems to cause # undefined references few layers deeper. Need further investigation, # if anybody cares. net-libs/ortp zrtp
revision 1.600 date: 2014-09-16 03:53:43 +0200; author: floppym; state: Exp; lines: +7 -1; commitid: 11b9541798264567; Move mgorny's last mask from use.mask to package.use.mask.