dnl CF_CHECK_CACHE version: 11 updated: 2008/03/23 14:45:59
dnl --------------
dnl Check if we're accidentally using a cache from a different machine.
dnl Derive the system name, as a check for reusing the autoconf cache.
dnl
dnl If we've packaged config.guess and config.sub, run that (since it does a
dnl better job than uname).  Normally we'll use AC_CANONICAL_HOST, but allow
dnl an extra parameter that we may override, e.g., for AC_CANONICAL_SYSTEM
dnl which is useful in cross-compiles.
dnl
dnl Note: we would use $ac_config_sub, but that is one of the places where
dnl autoconf 2.5x broke compatibility with autoconf 2.13
AC_DEFUN([CF_CHECK_CACHE],
[
if test -f $srcdir/config.guess || test -f $ac_aux_dir/config.guess ; then
	ifelse([$1],,[AC_CANONICAL_HOST],[$1])
	system_name="$host_os"
else
	system_name="`(uname -s -r) 2>/dev/null`"
	if test -z "$system_name" ; then
		system_name="`(hostname) 2>/dev/null`"
	fi
fi
test -n "$system_name" && AC_DEFINE_UNQUOTED(SYSTEM_NAME,"$system_name")
AC_CACHE_VAL(cf_cv_system_name,[cf_cv_system_name="$system_name"])

test -z "$system_name" && system_name="$cf_cv_system_name"
test -n "$cf_cv_system_name" && AC_MSG_RESULT(Configuring for $cf_cv_system_name)

if test ".$system_name" != ".$cf_cv_system_name" ; then
	AC_MSG_RESULT(Cached system name ($system_name) does not agree with actual ($cf_cv_system_name))
	AC_MSG_ERROR("Please remove config.cache and try again.")
fi
])dnl
