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

RS129.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015,2023 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
@@ -18,6 +18,8 @@
 
 #include "RS129.h"
 
+#if defined(USE_DMR)
+
 #include <cstdio>
 #include <cassert>
 #include <cstring>
@@ -128,3 +130,5 @@ bool CRS129::check(const unsigned char* in)
 	return in[9U] == parity[2U] && in[10U] == parity[1U] && in[11U] == parity[0U];
 }
 
+#endif
+