diff --git a/src/landscape.cpp b/src/landscape.cpp
index 4c45c46753..a386a637c5 100644
--- a/src/landscape.cpp
+++ b/src/landscape.cpp
@@ -610,6 +610,7 @@ CommandCost CmdClearArea(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 }
 
 
+TileIndex _cur_tileloop_tile;
 #define TILELOOP_BITS 4
 #define TILELOOP_SIZE (1 << TILELOOP_BITS)
 #define TILELOOP_ASSERTMASK ((TILELOOP_SIZE - 1) + ((TILELOOP_SIZE - 1) << MapLogX()))
diff --git a/src/misc.cpp b/src/misc.cpp
index 8b195d5fb4..5d91c295b0 100644
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -31,6 +31,7 @@
 #include "table/sprites.h"
 
 char _name_array[512][32];
+extern TileIndex _cur_tileloop_tile;
 
 void InitializeVehicles();
 void InitializeWaypoints();
diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
index f8faea2180..78053470d1 100644
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -567,6 +567,7 @@ static void ErrmsgWndProc(Window *w, WindowEvent *e)
 
 		case WE_DESTROY:
 			SetRedErrorSquare(0);
+			extern StringID _switch_mode_errorstr;
 			_switch_mode_errorstr = INVALID_STRING_ID;
 			break;
 
diff --git a/src/network/core/tcp.cpp b/src/network/core/tcp.cpp
index a4b763b1ad..f44f1741c9 100644
--- a/src/network/core/tcp.cpp
+++ b/src/network/core/tcp.cpp
@@ -75,6 +75,7 @@ NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection()
 	if (!_network_server && _networking) {
 		_switch_mode = SM_MENU;
 		_networking = false;
+		extern StringID _switch_mode_errorstr;
 		_switch_mode_errorstr = STR_NETWORK_ERR_LOSTCONNECTION;
 
 		return NETWORK_RECV_STATUS_CONN_LOST;
diff --git a/src/network/network.cpp b/src/network/network.cpp
index 8ec1a2a8ac..26009d749f 100644
--- a/src/network/network.cpp
+++ b/src/network/network.cpp
@@ -224,6 +224,7 @@ uint NetworkCalculateLag(const NetworkTCPSocketHandler *cs)
 static void NetworkError(StringID error_string)
 {
 	_switch_mode = SM_MENU;
+	extern StringID _switch_mode_errorstr;
 	_switch_mode_errorstr = error_string;
 }
 
diff --git a/src/network/network_client.cpp b/src/network/network_client.cpp
index 378e6de56b..abc5c62032 100644
--- a/src/network/network_client.cpp
+++ b/src/network/network_client.cpp
@@ -328,6 +328,7 @@ DEF_CLIENT_SEND_COMMAND_PARAM(PACKET_CLIENT_RCON)(const char *pass, const char *
 // **********
 
 extern bool SafeSaveOrLoad(const char *filename, int mode, int newgm, Subdirectory subdir);
+extern StringID _switch_mode_errorstr;
 
 DEF_CLIENT_RECEIVE_COMMAND(PACKET_SERVER_FULL)
 {
diff --git a/src/oldloader.cpp b/src/oldloader.cpp
index 103845a3d9..3f2ee4c35f 100644
--- a/src/oldloader.cpp
+++ b/src/oldloader.cpp
@@ -1473,6 +1473,7 @@ static bool LoadTTDPatchExtraChunks(LoadgameState *ls, int num)
 	return !ls->failed;
 }
 
+extern TileIndex _cur_tileloop_tile;
 static uint32 _old_cur_town_ctr;
 static const OldChunks main_chunk[] = {
 	OCL_ASSERT( 0 ),
diff --git a/src/openttd.cpp b/src/openttd.cpp
index 70bc76a459..cf4e23a37e 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -84,6 +84,8 @@
 
 #include "table/strings.h"
 
+StringID _switch_mode_errorstr;
+
 void CallLandscapeTick();
 void IncreaseDate();
 void DoPaletteAnimations();
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index fdfdf33640..bfcad9ba79 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -29,6 +29,7 @@
 #include "settings_type.h"
 #include "widgets/dropdown_type.h"
 #include "widgets/dropdown_func.h"
+#include "tunnelbridge.h"
 
 #include "bridge_map.h"
 #include "rail_map.h"
diff --git a/src/road_gui.cpp b/src/road_gui.cpp
index c483b3fa6e..2f184d7a9d 100644
--- a/src/road_gui.cpp
+++ b/src/road_gui.cpp
@@ -22,6 +22,7 @@
 #include "sound_func.h"
 #include "player_func.h"
 #include "settings_type.h"
+#include "tunnelbridge.h"
 
 #include "table/sprites.h"
 #include "table/strings.h"
diff --git a/src/tunnelbridge.h b/src/tunnelbridge.h
index 758ba59a56..88b42ae8c3 100644
--- a/src/tunnelbridge.h
+++ b/src/tunnelbridge.h
@@ -6,8 +6,6 @@
 #define TUNNELBRIDGE_H
 
 #include "tile_type.h"
-#include "map_func.h"
-#include "tunnelbridge_map.h"
 
 /**
  * Calculates the length of a tunnel or a bridge (without end tiles)
@@ -23,4 +21,6 @@ static inline uint GetTunnelBridgeLength(TileIndex begin, TileIndex end)
 	return abs(x2 + y2 - x1 - y1) - 1;
 }
 
+extern TileIndex _build_tunnel_endtile;
+
 #endif /* TUNNELBRIDGE_H */
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index 66b61b020b..109f86baf1 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -44,6 +44,7 @@
 #include "table/bridge_land.h"
 
 BridgeSpec _bridge[MAX_BRIDGES];
+TileIndex _build_tunnel_endtile;
 
 /** Reset the data been eventually changed by the grf loaded. */
 void ResetBridges()
diff --git a/src/variables.h b/src/variables.h
index a49fa32ce1..17bc0ceba6 100644
--- a/src/variables.h
+++ b/src/variables.h
@@ -5,18 +5,12 @@
 #ifndef VARIABLES_H
 #define VARIABLES_H
 
-#include "tile_type.h"
-#include "strings_type.h"
-
 /* Amount of game ticks */
 VARDEF uint16 _tick_counter;
 
 /* Skip aging of cargo? */
 VARDEF byte _age_cargo_skip_counter;
 
-/* Position in tile loop */
-VARDEF TileIndex _cur_tileloop_tile;
-
 /* Also save scrollpos_x, scrollpos_y and zoom */
 VARDEF uint16 _disaster_delay;
 
@@ -57,12 +51,10 @@ VARDEF int _caret_timer;
 VARDEF bool _rightclick_emulate;
 
 /* IN/OUT parameters to commands */
-VARDEF TileIndex _build_tunnel_endtile;
 VARDEF bool _generating_world;
 
 /* Used when switching from the intro menu. */
 VARDEF byte _switch_mode;
-VARDEF StringID _switch_mode_errorstr;
 
 VARDEF char _savegame_format[8];