diff --git a/src/openttd.cpp b/src/openttd.cpp
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -83,7 +83,7 @@ void ProcessAsyncSaveFinish();
 void CallWindowTickEvent();
 
 extern void SetDifficultyLevel(int mode, DifficultySettings *gm_opt);
-extern Company *DoStartupNewCompany(bool is_ai);
+extern Company *DoStartupNewCompany(bool is_ai, CompanyID company = INVALID_COMPANY);
 extern void ShowOSErrorBox(const char *buf, bool system);
 extern void InitializeRailGUI();