Make AX.25, DMR, P25, NXDN and FM selectable at compile time.

P25RX.h

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015,2016,2017 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015,2016,2017,2020 by Jonathan Naylor G4KLX
  *   Copyright (C) 2018 by Bryan Biedenkapp <[email protected]>
  *
  *   This program is free software; you can redistribute it and/or modify
@@ -17,10 +17,13 @@
  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include "Config.h"
+
+#if defined(MODE_P25)
+
 #if !defined(P25RX_H)
 #define  P25RX_H
 
-#include "Config.h"
 #include "P25Defines.h"
 
 enum P25RX_STATE {
@@ -72,3 +75,6 @@ private:
 };
 
 #endif
+
+#endif
+