AP_Declination: fixed build under SITL

libraries/AP_Declination/AP_Declination.cpp

@@ -194,7 +194,7 @@ AP_Declination::get_lookup_value(uint8_t x, uint8_t y)
 	for(i = start_index; i < (start_index + declination_keys[1][x]) && current_virtual_index <= y; i++){
 
 		// Pull out the row_value struct
-		memcpy_P((void*) &stval, (void *) &declination_values[i], sizeof(struct row_value));
+		memcpy_P((void*) &stval, (const prog_char *)&declination_values[i], sizeof(struct row_value));
 
 		// Pull the first offset and determine sign
 		offset = stval.abs_offset;

libraries/AP_Declination/examples/AP_Declination_test/AP_Declination_test.pde

@@ -5,6 +5,23 @@
 #include <AP_Common.h>
 #include <AP_Math.h>
 #include <AP_Declination.h>
+#include <Filter.h>
+
+#ifdef DESKTOP_BUILD
+// all of this is needed to build with SITL
+#include <DataFlash.h>
+#include <APM_RC.h>
+#include <GCS_MAVLink.h>
+#include <Arduino_Mega_ISR_Registry.h>
+#include <AP_PeriodicProcess.h>
+#include <AP_ADC.h>
+#include <AP_Baro.h>
+#include <AP_Compass.h>
+#include <AP_GPS.h>
+Arduino_Mega_ISR_Registry isr_registry;
+AP_Baro_BMP085_HIL      barometer;
+AP_Compass_HIL     compass;
+#endif
 
 FastSerialPort(Serial, 0);
 

libraries/AP_Declination/examples/AP_Declination_test/Makefile

@@ -1 +1,4 @@
 include ../../../AP_Common/Arduino.mk
+
+sitl:
+	make -f ../../../../libraries/Desktop/Desktop.mk