From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 6 Aug 2024 17:00:26 +0000 (-0700)
Subject: More defense against bad echo
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=12ecf0f4679997d033bfb9ae4dac01e24f3b561f;p=thirdparty%2Fautoconf.git

More defense against bad echo

* lib/autoconf/general.m4 (_AC_INIT_PARSE_ARGS)
(_AC_ARG_VAR_VALIDATE):
Defend against ‘echo’ interpreting ‘\’ or leading ‘-’.
(_AC_EVAL, _AC_EVAL_STDERR): Add to comment yet another reason
that these macros are obsolete and should be removed.  There’s no
point trying to change them as that’s more likely to hurt than
help the (zero?) callers who still use them.
---

diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index 2dfa3691..20c688ed 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -930,7 +930,7 @@ Try '$[0] --help' for more information])
 done
 
 if test -n "$ac_prev"; then
-  ac_option=--`echo $ac_prev | sed 's/_/-/g'`
+  ac_option=--`printf '%s\n' $ac_prev | sed 's/_/-/g'`
   AC_MSG_ERROR([missing argument to $ac_option])
 fi
 
@@ -1699,8 +1699,14 @@ for ac_var in $ac_precious_vars; do
     *)
       if test "x$ac_old_val" != "x$ac_new_val"; then
 	# differences in whitespace do not lead to failure.
-	ac_old_val_w=`echo x $ac_old_val`
-	ac_new_val_w=`echo x $ac_new_val`
+	ac_old_val_w=
+	for ac_val in x $ac_old_val; do
+	  ac_old_val_w="$ac_old_val_w $ac_val"
+	done
+	ac_new_val_w=
+	for ac_val in x $ac_new_val; do
+	  ac_new_val_w="$ac_new_val_w $ac_val"
+	done
 	if test "$ac_old_val_w" != "$ac_new_val_w"; then
 	  AS_MESSAGE([error: '$ac_var' has changed since the previous run:], 2)
 	  ac_cache_corrupted=:
@@ -2689,7 +2695,8 @@ AC_DEFUN([_AC_DO_LIMIT],
 # _AC_EVAL(COMMAND)
 # -----------------
 # Eval COMMAND, save the exit status in ac_status, and log it.
-# Unlike _AC_DO, this macro mishandles quoted arguments in some cases.
+# Unlike _AC_DO, this macro mishandles quoted arguments
+# and backslashes in some cases.
 # It is present only for backward compatibility with previous Autoconf versions.
 AC_DEFUN([_AC_EVAL],
 [_AC_RUN_LOG([eval $1],
@@ -2699,7 +2706,8 @@ AC_DEFUN([_AC_EVAL],
 # _AC_EVAL_STDERR(COMMAND)
 # ------------------------
 # Like _AC_RUN_LOG_STDERR, but eval (instead of running) COMMAND.
-# Unlike _AC_DO_STDERR, this macro mishandles quoted arguments in some cases.
+# Unlike _AC_DO_STDERR, this macro mishandles quoted arguments
+# and backslashes in some cases.
 # It is present only for backward compatibility with previous Autoconf versions.
 AC_DEFUN([_AC_EVAL_STDERR],
 [_AC_RUN_LOG_STDERR([eval $1],