Allow NSH date command with no RTC. This command is useful without an RTC too. Also, this permits testing on the simulator which never has an RTC

Documentation/NuttShell.html

@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttShell (NSH)</i></font></big></h1>
-      <p>Last Updated: August 7, 2014</p>
+      <p>Last Updated: April 11, 2015</p>
     </td>
   </tr>
 </table>
@@ -1181,7 +1181,6 @@ date [-s &quot;MMM DD HH:MM:SS YYYY&quot;]
 <p>
   <b>Synopsis</b>.
   Show or set the current date and time.
-  This command is only supported if the platform supported RTC hardware (<code>CONFIG_RTC=y</code>).
 </p>
 <p>
   Only one format is used both on display and when setting the date/time:
@@ -2568,7 +2567,7 @@ nsh>
   </tr>
   <tr>
     <td><b><code>date</code></b></td>
-    <td><code>CONFIG_RTC</code></td>
+    <td><br></td>
     <td><code>CONFIG_NSH_DISABLE_DATE</code></td>
   </tr>
   <tr>

libc/Kconfig

@@ -288,6 +288,7 @@ endif
 config TIME_EXTENDED
 	bool "Add day of week, year support"
 	default "n"
+	depends on !LIBC_LOCALTIME
 	---help---
 		Selecting TIME_EXTENDED adds tm_wday, tm_yday and tm_isdst
 		to the tm struct. This allows integration with 3rd party libraries

libc/time/lib_localtime.c

@@ -2158,6 +2158,7 @@ static time_t time2sub(struct tm *const tmp,
       li = y + (1 < yourtm.tm_mon);
       yourtm.tm_mday += year_lengths[isleap(li)];
     }
+
   while (yourtm.tm_mday > DAYSPERLYEAR)
     {
       li = y + (1 < yourtm.tm_mon);
@@ -2167,6 +2168,7 @@ static time_t time2sub(struct tm *const tmp,
           return -1;
         }
     }
+
   for (;;)
     {
       i = mon_lengths[isleap(y)][yourtm.tm_mon];