diff --git a/ChangeLog b/ChangeLog
index fe27f19f..1f46366d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2000-11-16  Akim Demaille  <akim@epita.fr>
+
+	* doc/autoconf.texi (Limitations of Usual Tools) <expr>:
+	expr 'a' : '\(b\)'.
+	From Paul Eggert.
+
 2000-11-16  Akim Demaille  <akim@epita.fr>
 
 	Reorder the test suite so that low level features are tested
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 5d123730..42accd26 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -5851,6 +5851,12 @@ Don't use @code{length}, @code{substr}, @code{match} and @code{index}.
 Don't use @samp{\?}, @samp{\+} and @samp{\|} in patterns, they are
 not supported on Solaris.
 
+The @sc{posix}.2-1996 standard is ambiguous as to whether @samp{expr 'a'
+: '\(b\)'} outputs @samp{0} or the empty string.  In practice, it
+outputs the empty string on most platforms, but portable scripts should
+not assume this.  For instance, the @sc{qnx} 4.2.5 native @command{expr}
+returns @samp{0}.
+
 Older @command{expr} implementations (e.g. SunOS 4 @command{expr} and
 Solaris 8 @command{/usr/ucb/expr}) have a silly length limit that causes
 @command{expr} to fail if the matched substring is longer than 120
diff --git a/tests/Makefile.in b/tests/Makefile.in
index 0f03f128..036c9c2f 100644
--- a/tests/Makefile.in
+++ b/tests/Makefile.in
@@ -66,7 +66,7 @@ standards_texi = @standards_texi@
 
 AUTOMAKE_OPTIONS = gnits
 
-SUITE = suite.at         m4sugar.at m4sh.at         base.at tools.at compile.at semantics.at torture.at syntax.at update.at
+SUITE = suite.at         m4sugar.at m4sh.at         base.at tools.at torture.at compile.at semantics.at syntax.at update.at
 
 
 # We don't actually distribute the testsuite, since one only