dnl ac_var_timeszone_externals.m4

# Define 'timezone', 'altzone' and 'daylight'

# http://www.gnu.org/software/ac-archive/Miscellaneous/ac_var_timezone_externals.html

# Use instead of 'AC_STRUCT_TIMEZONE' to determine whether the

# the external timezone variables 'timezone', 'altzone' and 'daylight' exist,

# defining 'HAVE_TIMEZONE', 'HAVE_ALTZONE' and 'HAVE_DAYLIGHT' respectively

# (as well as gaining the macros defined by 'AC_STRUCT_TIMEZONE').

# Mark R.Bannister <markb@freedomware.co.uk>

AC_DEFUN([AC_VAR_TIMEZONE_EXTERNALS],

[  AC_REQUIRE([AC_STRUCT_TIMEZONE])dnl

   AC_CACHE_CHECK(for timezone external, mb_cv_var_timezone,

   [  AC_TRY_LINK([#include <time.h>], [return (int)timezone;],

         mb_cv_var_timezone=yes,

         mb_cv_var_timezone=no)

   ])

   AC_CACHE_CHECK(for altzone external, mb_cv_var_altzone,

   [  AC_TRY_LINK([#include <time.h>], [return (int)altzone;],

         mb_cv_var_altzone=yes,

         mb_cv_var_altzone=no)

   ])

   AC_CACHE_CHECK(for daylight external, mb_cv_var_daylight,

   [  AC_TRY_LINK([#include <time.h>], [return (int)daylight;],

         mb_cv_var_daylight=yes,

         mb_cv_var_daylight=no)

   ])

   if test $mb_cv_var_timezone = yes; then

      AC_DEFINE([HAVE_TIMEZONE], 1,

              [Define if you have the external 'timezone' variable.])

   fi

   if test $mb_cv_var_altzone = yes; then

      AC_DEFINE([HAVE_ALTZONE], 1,

              [Define if you have the external 'altzone' variable.])

   fi

   if test $mb_cv_var_daylight = yes; then

      AC_DEFINE([HAVE_DAYLIGHT], 1,

              [Define if you have the external 'daylight' variable.])

   fi

])