--- autoconf-2.71/tests/local.at	2021-01-28 21:46:48.000000000 +0100
+++ autoconf-2.71-new/tests/local.at	2022-10-27 16:36:24.604217375 +0200
@@ -352,7 +352,7 @@ m4_define([AT_CHECK_CONFIGURE],
 # - AC_SUBST'ed variables
 #   (FIXME: Generate a list of these automatically.)
 # - _|@|.[*#?$].|argv|ARGC|LINENO|OLDPWD|PIPESTATUS|RANDOM|SECONDS
-#   |START_TIME|ToD|_AST_FEATURES
+#   |SHLVL|START_TIME|ToD|_AST_FEATURES
 #   Some variables some shells use and change.
 #   `.[*#?$].' catches `$#' etc. which are displayed like this:
 #      | '!'=18186
@@ -403,7 +403,7 @@ if test -f state-env.before && test -f s
       [GREP|[EF]GREP|SED],
       [[_@]|.[*@%:@?$].],
       [argv|ARGC|LINENO|BASH_ARGC|BASH_ARGV|OLDPWD|PIPESTATUS|RANDOM],
-      [SECONDS|START_TIME|ToD|_AST_FEATURES]))=' \
+      [SECONDS|SHLVL|START_TIME|ToD|_AST_FEATURES]))=' \
      $act_file ||
        test $? -eq 1 || echo failed >&2
     ) 2>stderr-$act_file |
@@ -434,6 +434,7 @@ fi
 #   - PPID [bash, zsh]
 #   - RANDOM [bash, zsh]
 #   - SECONDS [bash, zsh]
+#   - SHLVL [bash]
 #   - START_TIME [NetBSD sh]
 #   - ToD [NetBSD sh]
 #   - '$' [zsh]
@@ -481,6 +482,7 @@ do
 	/^PPID=/ d
 	/^RANDOM=/ d
 	/^SECONDS=/ d
+      /^SHLVL=/ d
 	/^START_TIME=/ d
 	/^ToD=/ d
 	/'\'\\\$\''=/ d