libgtk-2_0-0 from GNOME:STABLE:3.12 project
Select Your Operating System
Add repository and install manually
For openSUSE 13.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/GNOME:STABLE:3.12/openSUSE_13.1/GNOME:STABLE:3.12.repo zypper refresh zypper install libgtk-2_0-0