Merge pull request #1169 from zhaojuntao/gettimeofday

[libc] Add gettimeofday support to dlib

components/libc/compilers/dlib/time.c

+#include <sys/time.h>
+
+int gettimeofday(struct timeval *tp, void *ignore)
+{
+	time_t time;
+	rt_device_t device;
+
+	device = rt_device_find("rtc");
+	if (device != RT_NULL)
+	{
+		rt_device_control(device, RT_DEVICE_CTRL_RTC_GET_TIME, &time);
+		if (tp != RT_NULL)
+		{
+			tp->tv_sec = time;
+			tp->tv_usec = 0;
+		}
+
+		return time;
+	}
+
+	return 0;
+}
+