dnl
dnl --- DC_ARG_WITH(withname, description, varname, ifnot)
dnl
dnl
AC_DEFUN(DC_ARG_WITH, [
	AC_ARG_WITH($1, [$1: $2], [
		$3=$withval
	], [
		AC_CACHE_CHECK([$2], $3, [$4])
	])
])