Jason's GPS_None pointed out a few changes that in turn drastically simplify it.

libraries/AP_GPS/AP_GPS_None.cpp

@@ -1,19 +0,0 @@
-/*
-	AP_GPS_None.cpp			
-*/
-
-#include "AP_GPS_None.h"
-
-AP_GPS_None::AP_GPS_None()
-{
-}
-
-
-void AP_GPS_None::init(void)
-{	
-}
-
-void AP_GPS_None::update(void)
-{
-}
-

libraries/AP_GPS/AP_GPS_None.h

@@ -1,3 +1,5 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
+
 #ifndef AP_GPS_None_h
 #define AP_GPS_None_h
 
@@ -5,12 +7,5 @@
 
 class AP_GPS_None : public GPS
 {
-  public:
-	AP_GPS_None();
-	void init();
-	void update();
-
-  private:
-
 };
 #endif

libraries/AP_GPS/GPS.cpp

@@ -3,6 +3,16 @@
 #include "GPS.h"
 #include <stdio.h>
 
+void
+GPS::init(void)
+{
+}
+
+void
+GPS::update(void)
+{
+}
+
 void
 GPS::_error(const char *fmt, ...)
 {

libraries/AP_GPS/GPS.h

@@ -22,7 +22,7 @@ public:
 	///
 	/// @param	port	Stream connected to the GPS module.
 	///
-	GPS(Stream *port) : _port(port) {};
+	GPS(Stream *port = NULL) : _port(port) {};
 
 	/// Startup initialisation.
 	///