The first Glib::Object::Introspection ever (0.001) already requires GObject-Introspection 0.10.0 (we have 0.6.14), which requires Glib 2.24 (and we have 2.22.5). The Gtk is a disgracefully old 2.18 so it might not like the new Glib entirely, though I haven’t tested that — but I don’t want to cause instability on these machines (not to mention, upgrading packages them all would be a mess).