ref: eb78a94ed2d3a30cb40f2007d8bc7472966b6788
dir: /m4/ax_recursive_eval.m4/
# ===========================================================================
# https://www.gnu.org/software/autoconf-archive/ax_recursive_eval.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_RECURSIVE_EVAL(VALUE, RESULT)
#
# DESCRIPTION
#
# Interpolate the VALUE in loop until it doesn't change, and set the
# result to $RESULT. WARNING: It's easy to get an infinite loop with some
# unsane input.
#
# LICENSE
#
# Copyright (c) 2008 Alexandre Duret-Lutz <adl@gnu.org>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 1
AC_DEFUN([AX_RECURSIVE_EVAL],
[_lcl_receval="$1"
$2=`(test "x$prefix" = xNONE && prefix="$ac_default_prefix"
test "x$exec_prefix" = xNONE && exec_prefix="${prefix}"
_lcl_receval_old=''
while test "[$]_lcl_receval_old" != "[$]_lcl_receval"; do
_lcl_receval_old="[$]_lcl_receval"
eval _lcl_receval="\"[$]_lcl_receval\""
done
echo "[$]_lcl_receval")`])