Tools: Add EKF3 External Nav to build_options

Tools/scripts/build_options.py

@@ -32,7 +32,8 @@ BUILD_OPTIONS = [
     Feature('AHRS', 'EKF2', 'HAL_NAVEKF2_AVAILABLE', 'Enable EKF2', 0, None),
     Feature('AHRS', 'AHRS_EXT', 'HAL_EXTERNAL_AHRS_ENABLED', 'Enable External AHRS', 0, None),
     Feature('AHRS', 'TEMPCAL', 'HAL_INS_TEMPERATURE_CAL_ENABLE', 'Enable IMU Temperature Calibration', 0, None),
-    Feature('AHRS', 'VISUALODOM', 'HAL_VISUALODOM_ENABLED', 'Enable Visual Odometry', 0, None),
+    Feature('AHRS', 'VISUALODOM', 'HAL_VISUALODOM_ENABLED', 'Enable Visual Odometry', 0, 'EKF3_EXTNAV'),
+    Feature('AHRS', 'EKF3_EXTNAV', 'EK3_FEATURE_EXTERNAL_NAV', 'Enable External Navigation for EKF3', 0, None),
 
     Feature('Safety', 'PARACHUTE', 'HAL_PARACHUTE_ENABLED', 'Enable Parachute', 0, None),
     Feature('Safety', 'FENCE', 'AP_FENCE_ENABLED', 'Enable Geofence', 2, None),