make linkDirection more robust to member reordering

src/overworld.c

@@ -2931,7 +2931,7 @@ static void ZeroObjectEvent(struct ObjectEvent *objEvent)
 // conflict with the usual Event Object struct, thus the definitions.
 #define linkGender(obj) obj->singleMovementActive
 // not even one can reference *byte* aligned bitfield members...
-#define linkDirection(obj) ((u8 *)obj)[offsetof(typeof(*obj), fieldEffectSpriteId) - 1] // -> rangeX
+#define linkDirection(obj) ((u8 *)obj)[offsetof(typeof(*obj), range)] // -> rangeX
 
 static void SpawnLinkPlayerObjectEvent(u8 linkPlayerId, s16 x, s16 y, u8 gender)
 {