(svn r7022) -Fix [FS#292]: Properly guard against viewing company-sensitive information from

invalid players (eg spectators) which could lead to crashes.

rail_gui.c

@@ -589,7 +589,7 @@ void ShowBuildRailToolbar(RailType railtype, int button)
 {
 	Window *w;
 
-	if (_current_player == PLAYER_SPECTATOR) return;
+	if (!IsValidPlayer(_current_player)) return;
 	if (!ValParamRailtype(railtype)) return;
 
 	// don't recreate the window if we're clicking on a button and the window exists.