ext/date/extconf.rb: check for timezone and altzone

Instead of in configure.in. As of r28592 the HAVE_VAR_TIMEZONE and
HAVE_VAR_ALTZONE macros are only used by ext/date. ext/date doesn't care
whether they are int or long, so just check for the existence.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59939 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

configure.in

@@ -2805,35 +2805,6 @@ AC_CACHE_CHECK(for external int daylight, rb_cv_have_daylight,
 AS_IF([test "$rb_cv_have_daylight" = yes], [
   AC_DEFINE(HAVE_DAYLIGHT)
 ])
-AC_DEFUN([RUBY_CHECK_VARTYPE], [dnl
-AC_CACHE_CHECK([for external $1], AS_TR_SH(rb_cv_var_$1),
-  [AS_TR_SH(rb_cv_var_$1)=no
-  AC_TRY_COMPILE([
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 1
-#endif
-$2
-;
-const volatile void *volatile t;],
-    [t = &(&$1)[0];],
-    [for t in $3; do
-      AC_TRY_COMPILE([
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 1
-#endif
-$2
-;
-extern $t $1;
-const volatile void *volatile t;],
-        [t = &(&$1)[0];],
-        [AS_TR_SH(rb_cv_var_$1)=$t; break])
-    done])])
-AS_IF([test "${AS_TR_SH(rb_cv_var_$1)}" != no], [
-  AC_DEFINE(AS_TR_CPP(HAVE_VAR_$1))
-  AC_DEFINE_UNQUOTED(AS_TR_CPP(TYPEOF_VAR_$1), ${AS_TR_SH(rb_cv_var_$1)})
-])])
-RUBY_CHECK_VARTYPE(timezone, [@%:@include <time.h>], [long int])
-RUBY_CHECK_VARTYPE(altzone, [@%:@include <time.h>], [long int])
 
 AC_CACHE_CHECK(for negative time_t for gmtime(3), rb_cv_negative_time_t,
   [AC_TRY_RUN([

ext/date/date_core.c

@@ -7710,8 +7710,8 @@ datetime_s_now(int argc, VALUE *argv, VALUE klass)
 	s = 59;
 #ifdef HAVE_STRUCT_TM_TM_GMTOFF
     of = tm.tm_gmtoff;
-#elif defined(HAVE_VAR_TIMEZONE)
-#ifdef HAVE_VAR_ALTZONE
+#elif defined(HAVE_TIMEZONE)
+#ifdef HAVE_ALTZONE
     of = (long)-((tm.tm_isdst > 0) ? altzone : timezone);
 #else
     of = (long)-timezone;

ext/date/extconf.rb

@@ -1,4 +1,9 @@
 # frozen_string_literal: true
 require 'mkmf'
+
 config_string("strict_warnflags") {|w| $warnflags += " #{w}"}
+
+have_var("timezone", "time.h")
+have_var("altzone", "time.h")
+
 create_makefile('date_core')