Added detection of platforms which don't have external timezone and

configure

@@ -19760,6 +19760,129 @@ _ACEOF
 fi
 
 
+echo "$as_me:$LINENO: checking for timezone variable" >&5
+echo $ECHO_N "checking for timezone variable... $ECHO_C" >&6
+if test "${ac_cv_have_timezone+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <time.h>
+int
+main ()
+{
+timezone;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest$ac_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_have_timezone="yes"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ac_cv_have_timezone="no"
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: $ac_cv_have_timezone" >&5
+echo "${ECHO_T}$ac_cv_have_timezone" >&6
+if test "$ac_cv_have_timezone" = "yes"
+then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_TIMEZONE 1
+_ACEOF
+
+fi
+echo "$as_me:$LINENO: checking for daylight variable" >&5
+echo $ECHO_N "checking for daylight variable... $ECHO_C" >&6
+if test "${ac_cv_have_daylight+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <time.h>
+int
+main ()
+{
+daylight;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest$ac_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_have_daylight="yes"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ac_cv_have_daylight="no"
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: $ac_cv_have_daylight" >&5
+echo "${ECHO_T}$ac_cv_have_daylight" >&6
+if test "$ac_cv_have_daylight" = "yes"
+then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_DAYLIGHT 1
+_ACEOF
+
+fi
+
 
 case $host_cpu in
   *i[3456789]86*) echo "$as_me:$LINENO: checking whether we need to define __i386__" >&5

configure.ac

@@ -1474,6 +1474,22 @@ AC_CHECK_MEMBERS([struct option.name],,,
 dnl Check for stat.st_blocks
 AC_CHECK_MEMBERS([struct stat.st_blocks])
 
+dnl Check for the external timezone variables timezone and daylight
+AC_CACHE_CHECK([for timezone variable], ac_cv_have_timezone,
+               AC_TRY_LINK([#include <time.h>],[timezone;],
+			   ac_cv_have_timezone="yes", ac_cv_have_timezone="no"))
+if test "$ac_cv_have_timezone" = "yes"
+then
+    AC_DEFINE(HAVE_TIMEZONE, 1, [Define if you have the timezone variable])
+fi
+AC_CACHE_CHECK([for daylight variable], ac_cv_have_daylight,
+               AC_TRY_LINK([#include <time.h>],[daylight;],
+			   ac_cv_have_daylight="yes", ac_cv_have_daylight="no"))
+if test "$ac_cv_have_daylight" = "yes"
+then
+    AC_DEFINE(HAVE_DAYLIGHT, 1, [Define if you have the daylight variable])
+fi
+
 dnl *** check for the need to define platform-specific symbols
 
 case $host_cpu in

dlls/msvcrt/time.c

@@ -348,8 +348,26 @@ char **__p__tzname(void)
 void MSVCRT__tzset(void)
 {
     tzset();
+#if defined(HAVE_TIMEZONE) && defined(HAVE_DAYLIGHT)
     MSVCRT___daylight = daylight;
     MSVCRT___timezone = timezone;
+#else
+    {
+        static const time_t seconds_in_year = (365 * 24 + 6) * 3600;
+        time_t t;
+        struct tm *tmp;
+        long zone_january, zone_july;
+
+        t = (time((time_t *)0) / seconds_in_year) * seconds_in_year;
+        tmp = localtime(&t);
+        zone_january = -tmp->tm_gmtoff;
+        t += seconds_in_year / 2;
+        tmp = localtime(&t);
+        zone_july = -tmp->tm_gmtoff;
+        MSVCRT___daylight = (zone_january != zone_july);
+        MSVCRT___timezone = max(zone_january, zone_july);
+    }
+#endif
     lstrcpynA(tzname_std, tzname[0], sizeof(tzname_std));
     tzname_std[sizeof(tzname_std) - 1] = '\0';
     lstrcpynA(tzname_dst, tzname[1], sizeof(tzname_dst));

include/config.h.in

@@ -71,6 +71,9 @@
 /* Define to 1 if you have the <curses.h> header file. */
 #undef HAVE_CURSES_H
 
+/* Define if you have the daylight variable */
+#undef HAVE_DAYLIGHT
+
 /* Define to 1 if you have the <direct.h> header file. */
 #undef HAVE_DIRECT_H
 
@@ -740,6 +743,9 @@
 /* Define to 1 if you have the `timegm' function. */
 #undef HAVE_TIMEGM
 
+/* Define if you have the timezone variable */
+#undef HAVE_TIMEZONE
+
 /* Define to 1 if you have the <ucontext.h> header file. */
 #undef HAVE_UCONTEXT_H