mdate-sh vs. evil user/group names

[Eric Blake]

mdate-sh fails miserably in the presence of user/group names that contain 
spaces (bad practice, but particularly common on cygwin).  Currently, the 
script tries to figure out where the first field containing a month name 
appears when looking at /, then uses that information to grab the same field in 
the target file.  The net result when the two commands have a different number 
of fields, due to poorly placed spaces?  A horribly botched date string.

$ \ls -ld /
drwxrwx---+ 14 eblake Users 0 Feb  2 07:58 /
$ \ls -lLd doc/m4.texinfo 
-rw-r--r-- 1 eblake Domain Users 221922 Mar  1 14:50 doc/m4.texinfo
$ doc/mdate-sh doc/m4.texinfo 
Users February Mar

OK to apply this patch?

2007-03-01  Eric Blake  <address@hidden>

        * lib/mdate-sh (ls_command): Use -n when available to avoid
        problems with spaces in user/group names.

--- ../gnulib/build-aux/mdate-sh        2005-07-01 07:17:41.000000000 -0600
+++ lib/mdate-sh        2007-03-01 15:03:45.526362700 -0700
@@ -1,9 +1,9 @@
 #!/bin/sh
 # Get modification time of a file or directory and pretty-print it.
 
-scriptversion=2005-06-29.22
+scriptversion=2007-03-01.15
 
-# Copyright (C) 1995, 1996, 1997, 2003, 2004, 2005 Free Software
+# Copyright (C) 1995, 1996, 1997, 2003, 2004, 2005, 2007 Free Software
 # Foundation, Inc.
 # written by Ulrich Drepper <address@hidden>, June 1995
 #
@@ -75,6 +75,10 @@
 else
   ls_command='ls -l -d'
 fi
+# Avoid user/group names that might have spaces, when possible.
+if ls -n /dev/null 1>/dev/null 2>&1; then
+  ls_command="$ls_command -n"
+fi
 
 # A `ls -l' line looks as follows on OS/2.
 #  drwxrwx---        0 Aug 11  2001 foo
@@ -89,7 +93,7 @@
 # words should be skipped to get the date.
 
 # On HPUX /bin/sh, "set" interprets "-rw-r--r--" as options, so the "x" below.
-set x`ls -l -d /`
+set x`$ls_command /`
 
 # Find which argument is the month.
 month=