Ubuntu – unmet dependencies for synaptics touchpad driver

I have Ubuntu 14.04.2 installed on a Lenovo S21e-20. To get things like two-finger-scrolling or suspending the touchpad during typing, I wanted to install xserver-xorg-input-synaptics but installation fails with two unmet dependencies due to held broken packages (command outputs below). All those packages should be installed already by default (my installation is fresh, this is the first thing I do on this system after wi-fi driver installation).

Output of sudo apt-get install xserver-xorg-input-synaptics:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 xserver-xorg-input-synaptics : Depends: xorg-input-abi-20
                                Depends: xserver-xorg-core (>= 2:1.14.99.902)
E: Unable to correct problems, you have held broken packages.

Output of sudo apt-get install xorg-input-abi-20:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Note, selecting 'xserver-xorg-core' instead of 'xorg-input-abi-20'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 libcheese-gtk23 : Depends: libclutter-gtk-1.0-0 (>= 0.91.8) but it is  not going to be installed
               Depends: libcogl15 (>= 1.15.8) but it is not going to be installed
 libcheese7 : Depends: libclutter-gst-2.0-0 (>= 0.10.0) but it is not going to be installed
              Depends: gstreamer1.0-clutter but it is not going to be installed
 libclutter-1.0-0 : Depends: libcogl-pango15 (>= 1.15.8) but it is not going to be installed
                    Depends: libcogl15 (>= 1.15.8) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

Trying to install xserver-xorg-core aborts with a similar problem, i.e. the same unmet dependencies.

I tried sudo apt-get clean, sudo apt-get update, sudo dpkg --configure -a and sudo apt-get -f install, but all those did not solve the problem. No held packages are shown.

Trying to install the unment dependencies of xserver-xorg-core directly, shows that they are already installed.

How can I resolve this?