diff --git a/src/ai/api/ai_sign.cpp b/src/ai/api/ai_sign.cpp
--- a/src/ai/api/ai_sign.cpp
+++ b/src/ai/api/ai_sign.cpp
@@ -3,6 +3,7 @@
 /** @file ai_sign.cpp Implementation of AISign. */
 
 #include "ai_sign.hpp"
+#include "ai_log.hpp"
 #include "table/strings.h"
 #include "../ai_instance.hpp"
 #include "../../command_func.h"
diff --git a/src/ai/api/ai_tile.cpp b/src/ai/api/ai_tile.cpp
--- a/src/ai/api/ai_tile.cpp
+++ b/src/ai/api/ai_tile.cpp
@@ -5,6 +5,7 @@
 #include "ai_tile.hpp"
 #include "ai_map.hpp"
 #include "ai_town.hpp"
+#include "ai_log.hpp"
 #include "../../station_func.h"
 #include "../../company_func.h"
 #include "../../road_map.h"