--- a/aircraft_cmd.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/aircraft_cmd.c	Sun Dec 03 15:48:21 2006 +0000
@@ -207,7 +207,7 @@
 	const AirportFTAClass* ap;
 	Engine *e;
 
-	if (!IsEngineBuildable(p1, VEH_Aircraft)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
+	if (!IsEngineBuildable(p1, VEH_Aircraft, _current_player)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
 
 	value = EstimateAircraftCost(p1);
 

--- a/build_vehicle_gui.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/build_vehicle_gui.c	Sun Dec 03 15:48:21 2006 +0000
@@ -290,7 +290,7 @@
 	 * when planes become obsolete and are removed */
 	sel_id = INVALID_ENGINE;
 	for (eid = AIRCRAFT_ENGINES_INDEX; eid < AIRCRAFT_ENGINES_INDEX + NUM_AIRCRAFT_ENGINES; eid++) {
-		if (IsEngineBuildable(eid, VEH_Aircraft)) {
+		if (IsEngineBuildable(eid, VEH_Aircraft, _local_player)) {
 			const AircraftVehicleInfo *avi = AircraftVehInfo(eid);
 			switch (bv->filter.acc_planes) {
 				case HELICOPTERS_ONLY:

--- a/engine.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/engine.c	Sun Dec 03 15:48:21 2006 +0000
@@ -401,12 +401,13 @@
 
 /*
  * returns true if an engine is valid, of the specified type, and buildable by
- * the current player, false otherwise
+ * the given player, false otherwise
  *
  * engine = index of the engine to check
  * type   = the type the engine should be of (VEH_xxx)
+ * player = index of the player
  */
-bool IsEngineBuildable(uint engine, byte type)
+bool IsEngineBuildable(EngineID engine, byte type, PlayerID player)
 {
 	const Engine *e;
 
@@ -419,7 +420,7 @@
 	if (e->type != type) return false;
 
 	// check if it's available
-	if (!HASBIT(e->player_avail, _current_player)) return false;
+	if (!HASBIT(e->player_avail, player)) return false;
 
 	return true;
 }

--- a/engine.h	Sun Dec 03 13:40:16 2006 +0000
+++ b/engine.h	Sun Dec 03 15:48:21 2006 +0000
@@ -137,7 +137,7 @@
 void LoadCustomEngineNames(void);
 void DeleteCustomEngineNames(void);
 
-bool IsEngineBuildable(uint engine, byte type);
+bool IsEngineBuildable(EngineID engine, byte type, PlayerID player);
 
 enum {
 	NUM_NORMAL_RAIL_ENGINES = 54,

--- a/roadveh_cmd.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/roadveh_cmd.c	Sun Dec 03 15:48:21 2006 +0000
@@ -114,7 +114,7 @@
 	UnitID unit_num;
 	Engine *e;
 
-	if (!IsEngineBuildable(p1, VEH_Road)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
+	if (!IsEngineBuildable(p1, VEH_Road, _current_player)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
 
 	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
 

--- a/ship_cmd.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/ship_cmd.c	Sun Dec 03 15:48:21 2006 +0000
@@ -814,7 +814,7 @@
 	UnitID unit_num;
 	Engine *e;
 
-	if (!IsEngineBuildable(p1, VEH_Ship)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
+	if (!IsEngineBuildable(p1, VEH_Ship, _current_player)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
 
 	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);
 

--- a/train_cmd.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/train_cmd.c	Sun Dec 03 15:48:21 2006 +0000
@@ -743,7 +743,7 @@
 	uint num_vehicles;
 
 	/* Check if the engine-type is valid (for the player) */
-	if (!IsEngineBuildable(p1, VEH_Train)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
+	if (!IsEngineBuildable(p1, VEH_Train, _current_player)) return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
 
 	/* Check if the train is actually being built in a depot belonging
 	 * to the player. Doesn't matter if only the cost is queried */

--- a/train_gui.c	Sun Dec 03 13:40:16 2006 +0000
+++ b/train_gui.c	Sun Dec 03 15:48:21 2006 +0000
@@ -393,7 +393,7 @@
 		const RailVehicleInfo *rvi = RailVehInfo(eid);
 
 		if (bv->filter.railtype != RAILTYPE_END && !HasPowerOnRail(e->railtype, bv->filter.railtype)) continue;
-		if (!IsEngineBuildable(eid, VEH_Train)) continue;
+		if (!IsEngineBuildable(eid, VEH_Train, _local_player)) continue;
 
 		EngList_Add(&bv->eng_list, eid);
 		if ((rvi->flags & RVI_WAGON) == 0) {