From 8e2cdb066af972ddb93eb27bb1f7cdb51193c5e5 Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Sun, 28 Jan 2007 16:10:39 +0000
Subject: [PATCH] Simplify macrology that creates unistd.h.

---
 ChangeLog      |  8 ++++++++
 m4/fchdir.m4   |  9 ++++-----
 m4/unistd_h.m4 | 19 +++++++++++++------
 modules/fchdir |  2 +-
 4 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 41d153cca..886120a6c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2007-01-28  Bruno Haible  <bruno@clisp.org>
 
+	* m4/unistd_h.m4 (gl_HEADER_UNISTD_DEFAULTS): New macro.
+	(gl_HEADER_UNISTD): Require it. Don't set UNISTD_H to empty here.
+	* m4/fchdir.m4 (gl_FUNC_FCHDIR): Require gl_HEADER_UNISTD_DEFAULTS.
+	Set UNISTD_H instead of UNISTD_H2.
+	* modules/fchdir (BUILT_SOURCES): Drop $(UNISTD_H2).
+
+2007-01-28  Bruno Haible  <bruno@clisp.org>
+
 	* modules/mbchar (Makefile.am): Add mbchar.c to lib_SOURCES.
 	* m4/mbchar.m4 (gl_MBCHAR): Remove AC_LIBOBJ invocation.
 
diff --git a/m4/fchdir.m4 b/m4/fchdir.m4
index caebfcbe0..6998eae43 100644
--- a/m4/fchdir.m4
+++ b/m4/fchdir.m4
@@ -1,11 +1,12 @@
-# fchdir.m4 serial 1
-dnl Copyright (C) 2006 Free Software Foundation, Inc.
+# fchdir.m4 serial 2
+dnl Copyright (C) 2006-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_FCHDIR],
 [
+  AC_REQUIRE([gl_HEADER_UNISTD_DEFAULTS])
   AC_CHECK_FUNCS_ONCE([fchdir])
   if test $ac_cv_func_fchdir = no; then
     AC_LIBOBJ([fchdir])
@@ -15,14 +16,12 @@ AC_DEFUN([gl_FUNC_FCHDIR],
     gl_ABSOLUTE_HEADER([dirent.h])
     ABSOLUTE_DIRENT_H=\"$gl_cv_absolute_dirent_h\"
     DIRENT_H='dirent.h'
-    UNISTD_H2='unistd.h'
+    UNISTD_H='unistd.h'
   else
     DIRENT_H=
-    UNISTD_H2=
   fi
   AC_SUBST([ABSOLUTE_DIRENT_H])
   AC_SUBST([DIRENT_H])
-  AC_SUBST([UNISTD_H2])
 ])
 
 # Prerequisites of lib/fchdir.c.
diff --git a/m4/unistd_h.m4 b/m4/unistd_h.m4
index 9d499dfe8..d38de90fe 100644
--- a/m4/unistd_h.m4
+++ b/m4/unistd_h.m4
@@ -1,5 +1,5 @@
-# unistd_h.m4 serial 3
-dnl Copyright (C) 2006 Free Software Foundation, Inc.
+# unistd_h.m4 serial 4
+dnl Copyright (C) 2006-2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,12 +8,13 @@ dnl Written by Simon Josefsson
 
 AC_DEFUN([gl_HEADER_UNISTD],
 [
-  AC_CHECK_HEADERS([unistd.h], [
-    UNISTD_H=''
-  ], [
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_HEADER_UNISTD_DEFAULTS])
+
+  AC_CHECK_HEADERS([unistd.h], [], [
     UNISTD_H='unistd.h'
   ])
-  AC_SUBST(UNISTD_H)
   dnl This module decides to build unistd.h if it is missing.
   dnl The fchdir module decides to build unistd.h if fchdir() is missing.
   dnl Therefore check for the prerequisites of lib/unistd.h always.
@@ -30,3 +31,9 @@ AC_DEFUN([gl_PREREQ_UNISTD],
   fi
   AC_SUBST([ABSOLUTE_UNISTD_H])
 ])
+
+AC_DEFUN([gl_HEADER_UNISTD_DEFAULTS],
+[
+  UNISTD_H=
+  AC_SUBST(UNISTD_H)
+])
diff --git a/modules/fchdir b/modules/fchdir
index f3d177fae..8d9fca812 100644
--- a/modules/fchdir
+++ b/modules/fchdir
@@ -18,7 +18,7 @@ configure.ac:
 gl_FUNC_FCHDIR
 
 Makefile.am:
-BUILT_SOURCES += $(DIRENT_H) $(UNISTD_H2)
+BUILT_SOURCES += $(DIRENT_H)
 
 # We need the following in order to create <dirent.h> when the system
 # doesn't have one that works with the given compiler.
-- 
2.11.0