make -DGPS flag useful: if it exists it should work

conf/airframes/AirborneCodeReorg/TinyFw.xml

@@ -162,14 +162,12 @@
 
   <firmware name="fixedwing">
     <target name="ap" 			board="tiny_2.11">
-      <param name="FLASH_MODE" 		value="IAP" />
       <define name="AGR_CLIMB" />
       <define name="ALT_KALMAN" />
-      <define name="GENERIC" value="1" />
     </target>
     <target name="sim" 			board="pc" />
 
-    <subsystem name="radio_control" 	type="ppm"/>
+    <subsystem name="radio_control" 	type="ppm" />
 
     <!-- Communication -->
     <subsystem name="telemetry" 	type="transparent">

sw/airborne/gps.h

@@ -27,7 +27,6 @@
  *
 */
 
-
 #ifndef GPS_H
 #define GPS_H
 
@@ -120,6 +119,12 @@ extern struct svinfo gps_svinfos[GPS_NB_CHANNELS];
 #define GpsToggleLed() {}
 #endif
 
+#ifdef GPS
+#define GpsTimeoutError (cpu_time_sec - last_gps_msg_t > FAILSAFE_DELAY_WITHOUT_GPS)
+#else
+#define GpsTimeoutError 1
+#endif
+
 #define UseGpsPosNoSend(_callback) {			\
     if (GpsFixValid()) {			\
       last_gps_msg_t = cpu_time_sec;		\

sw/airborne/main_ap.c

@@ -193,6 +193,7 @@ float energy; 		// Fuel consumption (mAh)
 
 bool_t gps_lost = FALSE;
 
+
 #define Min(x, y) (x < y ? x : y)
 #define Max(x, y) (x > y ? x : y)
 
@@ -346,7 +347,7 @@ static void navigation_task( void ) {
   /** If aircraft is launched and is in autonomus mode, go into
       PPRZ_MODE_GPS_OUT_OF_ORDER mode (Failsafe) if we lost the GPS */
   if (launch) {
-    if (cpu_time_sec - last_gps_msg_t > FAILSAFE_DELAY_WITHOUT_GPS) {
+    if (GpsTimeoutError) {
       if (pprz_mode == PPRZ_MODE_AUTO2 || pprz_mode == PPRZ_MODE_HOME) {
 	last_pprz_mode = pprz_mode;
 	pprz_mode = PPRZ_MODE_GPS_OUT_OF_ORDER;