Don't run AC_STRUCT_TIMEZONE twice. (GH-9305)

configure

@@ -15344,77 +15344,6 @@ $as_echo "#define HAVE_BROKEN_POLL 1" >>confdefs.h
 
 fi
 
-# Before we can test tzset, we need to check if struct tm has a tm_zone
-# (which is not required by ISO C or UNIX spec) and/or if we support
-# tzname[]
-ac_fn_c_check_member "$LINENO" "struct tm" "tm_zone" "ac_cv_member_struct_tm_tm_zone" "#include <sys/types.h>
-#include <$ac_cv_struct_tm>
-
-"
-if test "x$ac_cv_member_struct_tm_tm_zone" = xyes; then :
-
-cat >>confdefs.h <<_ACEOF
-#define HAVE_STRUCT_TM_TM_ZONE 1
-_ACEOF
-
-
-fi
-
-if test "$ac_cv_member_struct_tm_tm_zone" = yes; then
-
-$as_echo "#define HAVE_TM_ZONE 1" >>confdefs.h
-
-else
-  ac_fn_c_check_decl "$LINENO" "tzname" "ac_cv_have_decl_tzname" "#include <time.h>
-"
-if test "x$ac_cv_have_decl_tzname" = xyes; then :
-  ac_have_decl=1
-else
-  ac_have_decl=0
-fi
-
-cat >>confdefs.h <<_ACEOF
-#define HAVE_DECL_TZNAME $ac_have_decl
-_ACEOF
-
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for tzname" >&5
-$as_echo_n "checking for tzname... " >&6; }
-if ${ac_cv_var_tzname+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <time.h>
-#if !HAVE_DECL_TZNAME
-extern char *tzname[];
-#endif
-
-int
-main ()
-{
-return tzname[0][0];
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_var_tzname=yes
-else
-  ac_cv_var_tzname=no
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext conftest.$ac_ext
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_var_tzname" >&5
-$as_echo "$ac_cv_var_tzname" >&6; }
-  if test $ac_cv_var_tzname = yes; then
-
-$as_echo "#define HAVE_TZNAME 1" >>confdefs.h
-
-  fi
-fi
-
-
 # check tzset(3) exists and works like we expect it to
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for working tzset()" >&5
 $as_echo_n "checking for working tzset()... " >&6; }

configure.ac

@@ -4744,11 +4744,6 @@ then
       [Define if poll() sets errno on invalid file descriptors.])
 fi
 
-# Before we can test tzset, we need to check if struct tm has a tm_zone
-# (which is not required by ISO C or UNIX spec) and/or if we support
-# tzname[]
-AC_STRUCT_TIMEZONE
-
 # check tzset(3) exists and works like we expect it to
 AC_MSG_CHECKING(for working tzset())
 AC_CACHE_VAL(ac_cv_working_tzset, [