4.19.1 - Allow callers to determine if a returned icon is a fallback icon - Remove duplicate _get_icon() code - Return correct fallback icon for XfwWindowWayland - Cache GIcon and GdkPixbuf in XfwApplication - Cache GIcon and GdkPixbuf in XfwWindow - Add xfw_(window|application)_get_gicon() - XfwApplication: Make XfwApplicationInstance opaque - Fix build when X11 disabled