Move the Super I/O game port flag to a #define

src/game/gameport.c

@@ -360,7 +360,7 @@ gameport_add(const device_t *gameport_type)
 {
     /* Prevent a standalone game port from being added later on, unless this
        is an unused Super I/O game port (no MACHINE_GAMEPORT machine flag). */
-    if (!(gameport_type->local & 0x1000000) || (machines[machine].flags & MACHINE_GAMEPORT))
+    if (!(gameport_type->local & GAMEPORT_SIO) || (machines[machine].flags & MACHINE_GAMEPORT))
 	standalone_gameport_type = NULL;
 
     /* Add game port device. */

src/include/86box/gameport.h

@@ -33,6 +33,7 @@
 
 #define JOYSTICK_PRESENT(n)	(joystick_state[n].plat_joystick_nr != 0)
 
+#define GAMEPORT_SIO		0x1000000
 
 typedef struct {
     char	name[260];