diff --git a/src/strings_internal.h b/src/strings_internal.h
--- a/src/strings_internal.h
+++ b/src/strings_internal.h
@@ -10,6 +10,8 @@
 #ifndef STRINGS_INTERNAL_H
 #define STRINGS_INTERNAL_H
 
+#include "strings_func.h"
+
 /**
  * Equivalent to the std::back_insert_iterator in function, with some
  * convenience helpers for string concatenation.
@@ -130,4 +132,10 @@ public:
 	}
 };
 
+void GetStringWithArgs(StringBuilder &builder, StringID string, StringParameters *args, uint case_index = 0, bool game_script = false);
+
+/* Do not leak the StringBuilder to everywhere. */
+void GetTownName(StringBuilder &builder, const struct Town *t);
+void GRFTownNameGenerate(StringBuilder &builder, uint32 grfid, uint16 gen, uint32 seed);
+
 #endif /* STRINGS_INTERNAL_H */