Update MentOs code to the latest development version.

programs/date.c

@@ -0,0 +1,22 @@
+///                MentOS, The Mentoring Operating system project
+/// @file date.c
+/// @brief `date` program.
+/// @copyright (c) 2014-2021 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include <stdio.h>
+#include <time.h>
+
+int main(int argc, char** argv)
+{
+    time_t rawtime = time(NULL);
+    printf("Seconds since 01/01/1970 : %u\n", rawtime);
+    tm_t* timeinfo = localtime(&rawtime);
+    printf(
+        "It's %2d:%2d:%2d, %d weekday, %02d/%02d/%4d\n",
+        timeinfo->tm_hour, timeinfo->tm_min, timeinfo->tm_sec,
+        timeinfo->tm_wday,
+        timeinfo->tm_mday, timeinfo->tm_mon, timeinfo->tm_year
+    );
+    return 0;
+}