])
+dnl idea taken from the autoconf mailing list, posted by
+dnl Timur I. Bakeyev timur@gnu.org,
+dnl http://mail.gnu.org/pipermail/autoconf/1999-October/008311.html
+dnl partly rewritten by Peter Stamfest <peter@stamfest.at>
+
+dnl This determines, if struct tm containes tm_gmtoff field
+dnl or we should use extern long int timezone.
+
+dnl Add the following to your acconfig.h:
+
+dnl /* Define if your struct tm has tm_gmtoff. */
+dnl #undef HAVE_TM_GMTOFF
+dnl #undef TM_GMTOFF
+dnl
+dnl /* Define if you don't have tm_gmtoff but do have the external timezone. */
+dnl #undef HAVE_TIMEZONE
+
+AC_DEFUN([GC_TIMEZONE], [
+ AC_REQUIRE([AC_STRUCT_TM])
+ AC_CACHE_CHECK([tm_gmtoff in struct tm], gq_cv_have_tm_gmtoff,
+ gq_cv_have_tm_gmtoff=no
+ AC_TRY_COMPILE([#include <time.h>
+ #include <$ac_cv_struct_tm>
+ ],
+ [struct tm t;
+ t.tm_gmtoff = 0;
+ exit(0);
+ ],
+ gq_cv_have_tm_gmtoff=yes
+ )
+ )
+
+ AC_CACHE_CHECK([__tm_gmtoff in struct tm], gq_cv_have___tm_gmtoff,
+ gq_cv_have___tm_gmtoff=no
+ AC_TRY_COMPILE([#include <time.h>
+ #include <$ac_cv_struct_tm>
+ ],
+ [struct tm t;
+ t.__tm_gmtoff = 0;
+ exit(0);
+ ],
+ gq_cv_have___tm_gmtoff=yes
+ )
+ )
+
+ if test "$gq_cv_have_tm_gmtoff" = yes ; then
+ AC_DEFINE(HAVE_TM_GMTOFF,1,[does tm have a tm_gmtoff member])
+ AC_DEFINE(TM_GMTOFF, tm_gmtoff,[the real name of tm_gmtoff])
+ elif test "$gq_cv_have___tm_gmtoff" = yes ; then
+ AC_DEFINE(HAVE_TM_GMTOFF)
+ AC_DEFINE(TM_GMTOFF, __tm_gmtoff)
+ else
+ AC_CACHE_CHECK(for timezone, ac_cv_var_timezone,
+ [AC_TRY_LINK([
+ #include <time.h>
+ extern long int timezone;
+ ],
+ [long int l = timezone;],
+ ac_cv_var_timezone=yes,
+ ac_cv_var_timezone=no)])
+ if test $ac_cv_var_timezone = yes; then
+ AC_DEFINE(HAVE_TIMEZONE,1,[is there an external timezone variable instead ?])
+ fi
+ fi
+])