diff --git a/src/os/macosx/macos.h b/src/os/macosx/macos.h
--- a/src/os/macosx/macos.h
+++ b/src/os/macosx/macos.h
@@ -11,15 +11,9 @@
  * the function then adds text that tells the user to update and then report the bug if it's present in the newest version
  * It also quits in a nice way since we call it when we know something happened that will crash OpenTTD (like a needed pointer turns out to be NULL or similar)
  */
-#ifdef __cplusplus
-extern "C" {
-#endif //__cplusplus
-	void ShowMacDialog ( const char *title, const char *message, const char *buttonLabel );
-	void ShowMacAssertDialog ( const char *function, const char *file, const int line, const char *expression );
-	void ShowMacErrorDialog(const char *error);
-#ifdef __cplusplus
-}
-#endif //__cplusplus
+void ShowMacDialog ( const char *title, const char *message, const char *buttonLabel );
+void ShowMacAssertDialog ( const char *function, const char *file, const int line, const char *expression );
+void ShowMacErrorDialog(const char *error);
 
 // Since MacOS X users will never see an assert unless they started the game from a terminal
 // we're using a custom assert(e) macro.