static int add_device(int model, struct libusb_device_descriptor *des,
const char *serial_num, const char *connection_id,
libusb_device *usbdev, GSList **devices)
static int add_device(int model, struct libusb_device_descriptor *des,
const char *serial_num, const char *connection_id,
libusb_device *usbdev, GSList **devices)