Added set time callback with optional offset for BACnet TimeSynchronization services (#691)

ports/win32/datetime-init.c

@@ -94,6 +94,19 @@ int gettimeofday(struct timeval *tp, void *tzp)
 }
 #endif
 
+/**
+ * @brief Set offset from the system clock.
+ * @param bdate BACnet Date structure to hold local time
+ * @param btime BACnet Time structure to hold local time
+ * @param utc - True for UTC sync, False for Local time
+ * @return True if time is set
+ */
+void datetime_timesync(
+    BACNET_DATE *bdate, BACNET_TIME *btime, bool utc)
+{
+    return;
+}
+
 /**
  * @brief Get the date, time, timezone, and UTC offset from system
  * @param utc_time - the BACnet Date and Time structure to hold UTC time