Merge tag '12.0-beta1' into jgrpp-beta

# Conflicts:
#	CMakeLists.txt
#	bin/ai/CMakeLists.txt
#	bin/game/CMakeLists.txt
#	src/build_vehicle_gui.cpp
#	src/console_cmds.cpp
#	src/core/overflowsafe_type.hpp
#	src/fios.cpp
#	src/lang/english.txt
#	src/lang/german.txt
#	src/lang/korean.txt
#	src/lang/polish.txt
#	src/network/core/game_info.cpp
#	src/network/core/game_info.h
#	src/network/core/tcp_game.cpp
#	src/network/core/tcp_game.h
#	src/network/network.cpp
#	src/network/network_client.cpp
#	src/network/network_client.h
#	src/network/network_coordinator.cpp
#	src/network/network_gui.cpp
#	src/network/network_server.cpp
#	src/network/network_server.h
#	src/newgrf_engine.cpp
#	src/openttd.cpp
#	src/rev.cpp.in
#	src/settings_type.h
#	src/train.h
#	src/train_cmd.cpp

src/newgrf_engine.h

@@ -100,8 +100,8 @@ bool UsesWagonOverride(const Vehicle *v);
 
 /* Handler to Evaluate callback 36. If the callback fails (i.e. most of the
  * time) orig_value is returned */
-uint GetVehicleProperty(const Vehicle *v, PropertyID property, uint orig_value);
-uint GetEngineProperty(EngineID engine, PropertyID property, uint orig_value, const Vehicle *v = nullptr);
+int GetVehicleProperty(const Vehicle *v, PropertyID property, int orig_value, bool is_signed = false);
+int GetEngineProperty(EngineID engine, PropertyID property, int orig_value, const Vehicle *v = nullptr, bool is_signed = false);
 
 enum VehicleTrigger {
 	VEHICLE_TRIGGER_NEW_CARGO     = 0x01,