giiEventSend - Inject an event into the input
int giiEventSend(gii_input_t inp, gii_event *ev);
giiEventSend injects an event into the queue. Such events can be
identified by (event->any.target == GII_EV_TARGET_QUEUE). There are
three main uses for this function:
1 Simulating input for independent subprograms.
2 Sending events to externally attached programs via specialized
inputs, that are actually rather outputs.
3 Sending command events to inputs, like querying the axis of a
giiEventSend returns 0 on success, or an gii-error(3) code otherwise.