kludgey patch for Ultrix4.4 failure

[Jim Meyering]

This fixes that nagging `illegal io' problem with Ultrix's /bin/sh.
(Thanks again for the account, Harlan!)

Here's a kludgey patch that shows what needs to be done.
I'm sure someone will find a way to induce the desired change
in a cleaner way, but I can't spend any more time on this today :-)

Here's a small example to illustrate the problem
  $ (eval echo > foo)

  illegal io

If you rewrite that slightly, it no longer fails:

  $ ((eval echo) > foo)
  $

That's what my patch does to similar code that autoconf
puts in nearly every configure file.

With this patch and the `missing' patch I just posted to the automake
list, fileutils-4.0.42 (coming soon) configures and compiles on Ultrix4.4.
It still fails a few tests on that system, but most seem to be due to
the fact that my idea of portable bourne shell scripts was inconsistent
with that implementation of /bin/sh :-)

Since I did manage to build `bash-2.04' on that system, I'm not sure how
much time I'll spend trying to make the test suite portable to it.

Index: acgeneral.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/acgeneral.m4,v
retrieving revision 1.702
diff -u -p -r1.702 acgeneral.m4
--- acgeneral.m4        2001/03/08 16:28:04     1.702
+++ acgeneral.m4        2001/03/17 22:52:26
@@ -2259,7 +2259,7 @@ AC_DEFUN([_AC_EVAL],
 # in ac_status, and log it.
 # Note that when tracing, most shells will leave the traces in stderr
 AC_DEFUN([_AC_EVAL_STDERR],
-[_AC_RUN_LOG_STDERR([eval $1],
+[_AC_RUN_LOG_STDERR([$1],
                     [eval echo "$as_me:__oline__: \"$1\""])])
 
 
@@ -2712,7 +2712,7 @@ m4_popdef([AC_Lib_Name])dnl
 # This macro can be used during the selection of a preprocessor.
 AC_DEFUN([_AC_PREPROC_IFELSE],
 [m4_ifvaln([$1], [AC_LANG_CONFTEST([$1])])dnl
-if _AC_EVAL_STDERR([$ac_cpp conftest.$ac_ext >/dev/null]); then
+if _AC_EVAL_STDERR([(eval $ac_cpp conftest.$ac_ext) >/dev/null]); then
   if test -s conftest.err; then
     ac_cpp_err=$ac_[]_AC_LANG_ABBREV[]_preproc_warn_flag
   else