Platform demos: Image Viewer example uses deprecated GtkStock
https://gitlab.gnome.org/GNOME/gnome-devel-docs/blob/master/platform-demos/C/image-viewer/image-viewer.c uses GtkStock which is deprecated since 3.10: https://developer.gnome.org/gtk3/stable/gtk3-Stock-Items.html#GTK-STOCK-CANCEL:CAPS