Fix bugs #641 and #9794 with %Z and current-time-zone on w32.

 nt/config.nt (HAVE_TZNAME, HAVE_DECL_TZNAME): Define.

nt/ChangeLog

+2011-10-19  Eli Zaretskii  <eliz@gnu.org>
+
+	* config.nt (HAVE_TZNAME, HAVE_DECL_TZNAME): Define.
+	(Bug#9794) (Bug#641)
+
 2011-09-04  Paul Eggert  <eggert@cs.ucla.edu>
 
 	* config.nt (HAVE_SNPRINTF): New macro.

nt/config.nt

@@ -187,7 +187,14 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #undef TM_IN_SYS_TIME
 #undef HAVE_TM_ZONE
-#undef HAVE_TZNAME
+
+/* Define to 1 if you don't have `tm_zone' but do have the external array
+   `tzname'. */
+#define HAVE_TZNAME 1
+
+/* Define to 1 if you have the declaration of `tzname', and to 0 if you don't.
+   */
+#define HAVE_DECL_TZNAME 1
 
 #undef const