*: fix a pile of directory and/or state retention related issues

m4/.gitignore

@@ -7,6 +7,7 @@
 !ax_prog_perl_modules.m4
 !ax_pthread.m4
 !ax_python.m4
+!ax_recursive_eval.m4
 !ax_sys_weak_alias.m4
 !ax_sys_weak_alias.m4
 !pkg.m4

m4/ax_recursive_eval.m4

@@ -0,0 +1,56 @@
+# ===========================================================================
+#    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 <[email protected]>
+#
+#   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")`])