I'm playing around with the Gtk3 exo library but I can't link against it. XDT_CHECK_PACKAGE([EXO], [exo-2], [0.10.6]) does not work, pkg-config complains that it cannot find exo-2. I installed the latest exo snapshot and manually checked the lib directory. libexo-2.so exists. So how can I use the minimal Gtk3 exo library?