Make all of the rest of the code base be conditionally compiled.

PseudoTTYController.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2020,2021 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2020,2021,2023 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -16,9 +16,12 @@
  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include "PseudoTTYController.h"
+
+#if defined(USE_AX25)
+
 #if !defined(_WIN32) && !defined(_WIN64)
 
-#include "PseudoTTYController.h"
 #include "Log.h"
 
 #include <cstring>
@@ -86,3 +89,6 @@ void CPseudoTTYController::close()
 }
 
 #endif
+
+#endif
+