AP_HAL: fixed example builds

libraries/AP_HAL/examples/Printf/Printf.pde

@@ -12,6 +12,7 @@
 #include <DataFlash.h>
 #include <GCS_MAVLink.h>
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 #include <AP_Compass.h>
 #include <AP_Declination.h>
 #include <SITL.h>

libraries/AP_HAL_AVR/examples/ArduCopterLibs/ArduCopterLibs.pde

@@ -37,6 +37,7 @@
 #include <AP_InertialNav.h>     // ArduPilot Mega inertial navigation library
 #include <GCS_MAVLink.h>
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 #include <memcheck.h>
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_APM2

libraries/AP_HAL_AVR/examples/ArduPlaneLibs/ArduPlaneLibs.pde

@@ -29,6 +29,7 @@
 #include <AP_Vehicle.h>
 #include <GCS_MAVLink.h>    // MAVLink GCS definitions
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 #include <AP_Mount.h>           // Camera/Antenna mount
 #include <AP_Declination.h> // ArduPilot Mega Declination Helper Library
 

libraries/AP_HAL_FLYMAPLE/examples/AP_Baro_BMP085_test/AP_Baro_BMP085_test.pde

@@ -19,6 +19,7 @@
 #include <DataFlash.h>
 #include <GCS_MAVLink.h>
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 
 #include <AP_HAL_FLYMAPLE.h>
 

libraries/AP_HAL_PX4/examples/simple/simple.pde

@@ -21,6 +21,7 @@
 #include <DataFlash.h>
 #include <GCS_MAVLink.h>
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 #include <AP_Param.h>
 #include <AP_Baro.h>
 #include <AP_Compass.h>