See http://www.mail-archive.com/bug-autoconf@gnu.org/msg01246.html

--- automake-1.9.6/tests/subst.test	2005-05-14 21:21:27.000000000 +0100
+++ automake-1.9.6/tests/subst.test	2008-11-23 08:29:01.000000000 +0000
@@ -1,5 +1,5 @@
 #! /bin/sh
-# Copyright (C) 1996, 2001, 2002  Free Software Foundation, Inc.
+# Copyright (C) 1996, 2001, 2002, 2007  Free Software Foundation, Inc.
 #
 # This file is part of GNU Automake.
 #
@@ -24,8 +24,14 @@
 . ./defs || exit 1
 
 cat >> configure.in << 'END'
-AC_SUBST($1)
-AC_SUBST([$]$1)  dnl this is the actual invocation that was used
+dnl This test used to have the following lines, which cannot have
+dnl worked sensibly with Autoconf for years, however:
+dnl AC_SUBST($1)
+dnl AC_SUBST([$]$1)  dnl this is the actual invocation that was used
+dnl
+AC_DEFUN([FOO],
+[AC_SUBST([$1])])
+FOO([BAR])
 END
 
 : > Makefile.am