diff --git a/ChangeLog b/ChangeLog
index bb2883ac..a43a69a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2001-03-19  Akim Demaille  <akim@epita.fr>
+
+	* acfunctions.m4 (AC_FUNC_STRERROR_R): Update to
+	fileutils-4.0.42's.
+
 2001-03-19  Akim Demaille  <akim@epita.fr>
 
 	* tests/atgeneral.m4 (AT_INIT): Don't always create `empty', rather
diff --git a/acfunctions.m4 b/acfunctions.m4
index 048027d6..f9bc8732 100644
--- a/acfunctions.m4
+++ b/acfunctions.m4
@@ -1283,7 +1283,8 @@ fi
 # AC_FUNC_STRERROR_R
 # ------------------
 AC_DEFUN([AC_FUNC_STRERROR_R],
-[AC_CHECK_FUNCS([strerror_r])
+[AC_CHECK_DECLS([strerror_r])
+AC_CHECK_FUNCS([strerror_r])
 if test $ac_cv_func_strerror_r = yes; then
   AC_CHECK_HEADERS(string.h)
   AC_CACHE_CHECK([for working strerror_r],
@@ -1297,14 +1298,42 @@ if test $ac_cv_func_strerror_r = yes; then
 #       endif
      ],
      [
-       char buf;
-       char x = *strerror_r (0, &buf, sizeof buf);
+       char buf[100];
+       char x = *strerror_r (0, buf, sizeof buf);
      ],
      ac_cv_func_strerror_r_works=yes,
      ac_cv_func_strerror_r_works=no
-    )])
+    )
+    if test $ac_cv_func_strerror_r_works = no; then
+      # strerror_r seems not to work, but now we have to choose between
+      # systems that have relatively inaccessible declarations for the
+      # function.  BeOS and DEC UNIX 4.0 fall in this category, but the
+      # former has a strerror_r that returns char*, while the latter
+      # has a strerror_r that returns `int'.
+      # This test should segfault on the DEC system.
+      AC_TRY_RUN(
+       [
+#       include <stdio.h>
+#       include <string.h>
+#       include <ctype.h>
+
+	extern char *strerror_r ();
+
+	int
+	main ()
+	{
+	  char buf[100];
+	  char x = *strerror_r (0, buf, sizeof buf);
+	  exit (!isalpha (x));
+	}
+       ],
+       ac_cv_func_strerror_r_works=yes,
+       ac_cv_func_strerror_r_works=no,
+       ac_cv_func_strerror_r_works=no)
+    fi
+  ])
   if test $ac_cv_func_strerror_r_works = yes; then
-    AC_DEFINE_UNQUOTED(HAVE_WORKING_STRERROR_R, 1,
+    AC_DEFINE_UNQUOTED([HAVE_WORKING_STRERROR_R], 1,
                        [Define to 1 if `strerror_r' returns a string.])
   fi
 fi
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 338a074a..e49fd1be 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -55,8 +55,8 @@ This file documents the GNU Autoconf package for creating scripts to
 configure source code packages using templates and an @code{m4} macro
 package.
 
-Copyright 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000 Free Software
-Foundation, Inc.
+Copyright 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001 Free
+Software Foundation, Inc.
 
 Permission is granted to make and distribute verbatim copies of this
 manual provided the copyright notice and this permission notice are
@@ -90,8 +90,8 @@ approved by the Foundation.
 
 @page
 @vskip 0pt plus 1filll
-Copyright @copyright{} 1992, 93, 94, 95, 96, 98, 99, 2000 Free Software
-Foundation, Inc.
+Copyright @copyright{} 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
+2001 Free Software Foundation, Inc.
 
 Permission is granted to make and distribute verbatim copies of this
 manual provided the copyright notice and this permission notice are
diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index 048027d6..f9bc8732 100644
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -1283,7 +1283,8 @@ fi
 # AC_FUNC_STRERROR_R
 # ------------------
 AC_DEFUN([AC_FUNC_STRERROR_R],
-[AC_CHECK_FUNCS([strerror_r])
+[AC_CHECK_DECLS([strerror_r])
+AC_CHECK_FUNCS([strerror_r])
 if test $ac_cv_func_strerror_r = yes; then
   AC_CHECK_HEADERS(string.h)
   AC_CACHE_CHECK([for working strerror_r],
@@ -1297,14 +1298,42 @@ if test $ac_cv_func_strerror_r = yes; then
 #       endif
      ],
      [
-       char buf;
-       char x = *strerror_r (0, &buf, sizeof buf);
+       char buf[100];
+       char x = *strerror_r (0, buf, sizeof buf);
      ],
      ac_cv_func_strerror_r_works=yes,
      ac_cv_func_strerror_r_works=no
-    )])
+    )
+    if test $ac_cv_func_strerror_r_works = no; then
+      # strerror_r seems not to work, but now we have to choose between
+      # systems that have relatively inaccessible declarations for the
+      # function.  BeOS and DEC UNIX 4.0 fall in this category, but the
+      # former has a strerror_r that returns char*, while the latter
+      # has a strerror_r that returns `int'.
+      # This test should segfault on the DEC system.
+      AC_TRY_RUN(
+       [
+#       include <stdio.h>
+#       include <string.h>
+#       include <ctype.h>
+
+	extern char *strerror_r ();
+
+	int
+	main ()
+	{
+	  char buf[100];
+	  char x = *strerror_r (0, buf, sizeof buf);
+	  exit (!isalpha (x));
+	}
+       ],
+       ac_cv_func_strerror_r_works=yes,
+       ac_cv_func_strerror_r_works=no,
+       ac_cv_func_strerror_r_works=no)
+    fi
+  ])
   if test $ac_cv_func_strerror_r_works = yes; then
-    AC_DEFINE_UNQUOTED(HAVE_WORKING_STRERROR_R, 1,
+    AC_DEFINE_UNQUOTED([HAVE_WORKING_STRERROR_R], 1,
                        [Define to 1 if `strerror_r' returns a string.])
   fi
 fi