diff --git a/engine.c b/engine.c
--- a/engine.c
+++ b/engine.c
@@ -829,7 +829,7 @@ StringID GetCustomEngineName(EngineID en
 }
 
 
-void AcceptEnginePreview(Engine *e, PlayerID player)
+static void AcceptEnginePreview(Engine *e, PlayerID player)
 {
 	Player *p = GetPlayer(player);