maint: avoid compiler warnings in m4 macros

[gnulib.git] / m4 / dirfd.m4

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index c377b87..02ddc9f 100644 (file)
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,9 +1,8 @@
-#serial 13   -*- Autoconf -*-
+# serial 17   -*- Autoconf -*-
 
 dnl Find out how to get the file descriptor associated with an open DIR*.
 
-# Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 Free Software
-# Foundation, Inc.
+# Copyright (C) 2001-2006, 2008-2009 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
@@ -12,15 +11,23 @@ dnl From Jim Meyering
 
 AC_DEFUN([gl_FUNC_DIRFD],
 [
-  AC_LIBSOURCES([dirfd.c, dirfd.h])
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  gl_REPLACE_DIRENT_H
+
+  dnl Persuade glibc <dirent.h> to declare dirfd().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
   dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
   AC_REQUIRE([AC_PROG_CPP])
   AC_REQUIRE([AC_PROG_EGREP])
-  AC_CHECK_FUNCS(dirfd)
+
+  AC_CHECK_FUNCS([dirfd])
   AC_CHECK_DECLS([dirfd], , ,
     [#include <sys/types.h>
      #include <dirent.h>])
+  if test $ac_cv_have_decl_dirfd = no; then
+    HAVE_DECL_DIRFD=0
+  fi
 
   AC_CACHE_CHECK([whether dirfd is a macro],
     gl_cv_func_dirfd_macro,
@@ -46,11 +53,11 @@ AC_DEFUN([gl_FUNC_DIRFD],
        for ac_expr in d_fd dd_fd; do
 
          CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
-         AC_TRY_COMPILE(
-           [#include <sys/types.h>
-            #include <dirent.h>],
-           [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
-           dir_fd_found=yes
+         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+            #include <sys/types.h>
+            #include <dirent.h>]],
+           [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
+           [dir_fd_found=yes]
          )
          CFLAGS=$dirfd_save_CFLAGS
          test "$dir_fd_found" = yes && break
@@ -61,7 +68,7 @@ AC_DEFUN([gl_FUNC_DIRFD],
       ]
     )
     if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
-      AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
+      AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME],
        $gl_cv_sys_dir_fd_member_name,
        [the name of the file descriptor member of DIR])
     fi