Problem solved, thank to this question and its answer (didn't find it at first as the title isn't very explicit, thus I don't withdraw my question, as it might be useful for others).
So, just in case, the solution is:
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get -f install
(and of course after that: apt-get upgrade and apt autoremoveto finalize).
