tar: don't worry about fdopendir closing its argument

* NEWS: Don't mention dirfd; no longer needed.
* gnulib.modules: Remove dirfd.
* src/create.c (get_directory_entries): Remove the code dealing
with dirfd failures, as the new fdopendir replacement doesn't
close its argument so we don't need to call dirfd.  See
<http://lists.gnu.org/archive/html/bug-gnulib/2010-09/msg00208.html>
and gnulib commit 970c9038e4cca46e1b037ae0a6d574dfae6a7327.

NEWS

@@ -18,7 +18,7 @@ modified while tar is creating an archive.  In the new approach, tar
 maintains a cache of file descriptors to directories, so it uses more
 file descriptors than before, but it adjusts to system limits on
 the number of file descriptors.  The new checks are implemented via
-the openat, dirfd, fdopendir, fstatat, and readlinkat calls
+the openat, fdopendir, fstatat, and readlinkat calls
 standardized by POSIX.1-2008.  On an older system where these calls do
 not exist or do not return useful results, tar emulates the calls at
 some cost in efficiency and reliability.

gnulib.modules

@@ -8,7 +8,6 @@ argp-version-etc
 backupfile
 closeout
 configmake
-dirfd
 dirname
 error
 exclude

src/create.c

@@ -1263,49 +1263,10 @@ open_failure_recover (struct tar_stat_info const *dir)
 char *
 get_directory_entries (struct tar_stat_info *st)
 {
-  DIR *dirstream;
-  while (! (dirstream = fdopendir (st->fd)) && open_failure_recover (st))
-    continue;
-
-  if (! dirstream)
-    return 0;
-  else
-    {
-      char *entries = streamsavedir (dirstream);
-      int streamsavedir_errno = errno;
-
-      int fd = dirfd (dirstream);
-      if (fd < 0)
-	{
-	  /* The dirent.h implementation doesn't use file descriptors
-	     for directory streams, so open the directory again.  */
-	  char const *name = st->orig_file_name;
-	  if (closedir (dirstream) != 0)
-	    close_diag (name);
-	  dirstream = 0;
-	  fd = subfile_open (st->parent,
-			     st->parent ? last_component (name) : name,
-			     open_searchdir_flags);
-	  if (fd < 0)
-	    fd = - errno;
-	  else
-	    {
-	      struct stat dirst;
-	      if (! (fstat (fd, &dirst) == 0
-		     && st->stat.st_ino == dirst.st_ino
-		     && st->stat.st_dev == dirst.st_dev))
-		{
-		  close (fd);
-		  fd = - IMPOSTOR_ERRNO;
-		}
-	    }
-	}
-
-      st->fd = fd;
-      st->dirstream = dirstream;
-      errno = streamsavedir_errno;
-      return entries;
-    }
+  while (! (st->dirstream = fdopendir (st->fd)))
+    if (! open_failure_recover (st))
+      return 0;
+  return streamsavedir (st->dirstream);
 }
 
 /* Dump the directory ST.  Return true if successful, false (emitting