Avoid implicit declaration of the Move_point function in

Wall_in_between_points in suibotdef.c.

diff --git a/src/server/server.h b/src/server/server.h

index 5c0cdd66de1db008..30b7f7d0a8fb09e4 100644

--- a/src/server/server.h

+++ b/src/server/server.h

@@ -151,6 +151,8 @@ void Groups_init(void);

 void Walls_init(void);

 void Treasure_init(void);

 void Move_init(void);

+struct collans;

+void Move_point(const move_t *move, struct collans *answer);

 void Move_object(object_t *obj);

 void Move_player(player_t *pl);

 void Turn_player(player_t *pl, bool push);