bug#19701: 24.3; directory-files platform-dependent behaviour when directory doesn't exist

["VIDA Gábor" <vidagabor@gmail.com>]

Hi!

On Linux when I specify a non-existing directory to directory-files, it signals an
error:

  (directory-files "abcd")
  eval: Opening directory: no such file or directory, /home/evidgbo/tmp/abcd

But on Windows, it returns nil:

  (directory-files "abcd")
  => nil

I think they should work tha same way regardless of the underlying system, and it
ends up in a Gnus error, what I will report separately once I understand that problem
better.

I used the official Windows version:

  GNU EMacs 24.3.1 (i386-mingw-nt6.1.7601) of 2013-03-17 on MARVIN

--
Thanks and regards,
Gábor Vida

In GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.10.7)
 of 2014-03-07 on lamiak, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11501000
System Description:	Ubuntu 14.04.1 LTS

Configured using:
 `configure '--build' 'x86_64-linux-gnu' '--build' 'x86_64-linux-gnu'
 '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib'
 '--localstatedir=/var/lib' '--infodir=/usr/share/info'
 '--mandir=/usr/share/man' '--with-pop=yes'
 '--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.3/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.3/site-lisp:/usr/share/emacs/site-lisp'
 '--with-crt-dir=/usr/lib/x86_64-linux-gnu' '--with-x=yes'
 '--with-x-toolkit=gtk3' '--with-toolkit-scroll-bars'
 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fstack-protector
 --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall'
 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

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  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

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