static void
device_added (CheeseCameraDeviceMonitor *monitor,
              CheeseCameraDevice        *device,
              UmPhotoDialog             *um)
{
        um->num_cameras++;
        update_photo_menu_status (um);
}
static void
device_removed (CheeseCameraDeviceMonitor *monitor,
                const char                *id,
                UmPhotoDialog             *um)
{
        um->num_cameras--;
        update_photo_menu_status (um);
}
static void
device_added (CheeseCameraDeviceMonitor *monitor,
              const gchar               *id,
              const gchar               *device_file,
              const gchar               *product_name,
              gint                       api_version,
              UmPhotoDialog             *um)
{
        um->num_cameras++;
        update_photo_menu_status (um);
}