acinclude/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
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#   option) any later version.
#
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#   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.
#
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#   with this program. If not, see <https://www.gnu.org/licenses/>.
#
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#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")`])