sekito: add hook

games/sekitoio/backend.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include <stdint.h>
+
+#include "sekitoio/sekitoio.h"
+
+struct sekito_io_backend {
+    void (*get_gamebtns)(uint32_t *gamebtn);
+    void (*get_trackball)(uint16_t *x, uint16_t *y);
+};