--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2011-07-25  Bruno Haible  <bruno@clisp.org>
 
+	dup3: Remove potential call-in from fchdir.m4.
+	* m4/dup3.m4 (gl_FUNC_DUP3): Add comment about fchdir.
+	* m4/fchdir.m4 (gl_FUNC_FCHDIR): Remove comment about dup3.
+
 	dup2: Move AC_LIBOBJ invocation to module description.
 	* m4/dup2.m4 (gl_REPLACE_DUP2): Remove macro.
 	(gl_FUNC_DUP2): Instead of gl_REPLACE_DUP2, just set REPLACE_DUP2 to 1.

--- a/m4/dup3.m4
+++ b/m4/dup3.m4
@@ -1,4 +1,4 @@
-# dup3.m4 serial 2
+# dup3.m4 serial 3
 dnl Copyright (C) 2009-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -15,4 +15,14 @@
   if test $ac_cv_func_dup3 != yes; then
     HAVE_DUP3=0
   fi
+
+dnl Not needed yet, because dup3 is unconditionally replaced.
+dnl  dnl Replace dup3() for supporting the gnulib-defined fchdir() function,
+dnl  dnl to keep fchdir's bookkeeping up-to-date.
+dnl  m4_ifdef([gl_FUNC_FCHDIR], [
+dnl    gl_TEST_FCHDIR
+dnl    if test $HAVE_FCHDIR = 0; then
+dnl      REPLACE_DUP3=1
+dnl    fi
+dnl  ])
 ])

--- a/m4/fchdir.m4
+++ b/m4/fchdir.m4
@@ -27,7 +27,6 @@
     REPLACE_OPENDIR=1
     REPLACE_CLOSEDIR=1
     REPLACE_DUP=1
-    dnl dup3 is already unconditionally replaced
     gl_REPLACE_FCNTL
     AC_CACHE_CHECK([whether open can visit directories],
       [gl_cv_func_open_directory_works],