AP_BoardConfig: instantiate an RTC

AP_BoardConfig: set RTC from hw clock at startup

libraries/AP_BoardConfig/AP_BoardConfig.cpp

@@ -21,6 +21,7 @@
 #include <GCS_MAVLink/GCS.h>
 #include "AP_BoardConfig.h"
 #include <stdio.h>
+#include <AP_RTC/AP_RTC.h>
 
 #if HAL_WITH_UAVCAN
 #include <AP_UAVCAN/AP_UAVCAN.h>
@@ -227,6 +228,8 @@ void AP_BoardConfig::init()
     // rebooting
     hal.util->set_imu_target_temp((int8_t *)&_imu_target_temperature);
 #endif
+
+    AP::rtc().set_utc_usec(hal.util->get_hw_rtc(), AP_RTC::SOURCE_HW);
 }
 
 // set default value for BRD_SAFETY_MASK

libraries/AP_BoardConfig/AP_BoardConfig.h

@@ -3,6 +3,7 @@
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Common/AP_Common.h>
 #include <AP_Param/AP_Param.h>
+#include <AP_RTC/AP_RTC.h>
 
 #if defined(HAL_NEEDS_PARAM_HELPER)
 #include <AP_Param_Helper/AP_Param_Helper.h>
@@ -214,4 +215,7 @@ private:
     // HAL specific parameters
     AP_Param_Helper param_helper{false};
 #endif
+
+    // real-time-clock; private because access is via the singleton
+    AP_RTC rtc;
 };