bug#25145: 25.1; clipboard-yank and associated functions are broken

[Stephane Chauveau <schauveau@nvidia.com>]

I noticed that the functions clipboard-yank, clipboard-kill-ring-save
and clipboard-kill-region are not accessing the gui clipboard as they
use to.

In previous version those 3 functions were setting
x-select-enable-clipbard to enable the clipboard.

They are now setting gui-select-enable-clipboard.

The problem is likely related to the recent renaming of
x-select-enable-clibboard into select-enable-clipboard (so without a
gui- prefix).

The variable gui-select-enable-clipboard is set in a few other places
but, as far as I can tell, it is never used for anything.


In GNU Emacs 25.1.1 (x86_64-unknown-linux-gnu)
  of 2016-11-18 built on vogt
Windowing system distributor 'The X.Org Foundation', version 11.0.11501000
System Description:    Linux Mint 17.1 Rebecca

Configured using:
  'configure --prefix=/home/schauveau/opt/emacs-25.1 --with-x-toolkit=no
  --with-xpm=no --with-gif=no'

Configured features:
JPEG TIFF PNG SOUND DBUS GSETTINGS NOTIFY GNUTLS LIBXML2 ZLIB X11

Important settings:
   value of $LC_COLLATE: C
   value of $LANG: en_US.UTF-8
   locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
   show-paren-mode: t
   display-time-mode: t
   shell-dirtrack-mode: t
   tooltip-mode: t
   global-eldoc-mode: t
   electric-indent-mode: t
   mouse-wheel-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   size-indication-mode: t
   column-number-mode: t
   line-number-mode: t
   transient-mark-mode: t

Recent messages:
Type C-x 1 to delete the help window.
uncompressing menu-bar.el.gz...done
Mark set
M-s C-g is undefined
Quit
Making completion list...

You can run the command ‘describe-variable’ with C-h v
uncompressing select.el.gz...done
Making completion list... [2 times]

Load-path shadows:
~/usr/share/emacs/xt-mouse hides 
/home/schauveau/opt/emacs-25.1/share/emacs/25.1/lisp/xt-mouse

Features:
(shadow sort mail-extr emacsbug message dired rfc822 mml mml-sec
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mail-utils pp jka-compr
windmove eieio-opt speedbar sb-image ezimage dframe find-func thingatpt
compile edmacro kmacro ido paren time tramp tramp-compat auth-source
cl-seq eieio eieio-core cl-macs gnus-util mm-util help-fns mail-prsvr
password-cache tramp-loaddefs trampver ucs-normalize shell pcomplete
comint ansi-color ring format-spec advice finder-inf info
chess-autoloads etags-select-autoloads xpm-autoloads package seq
byte-opt gv bytecomp byte-compile cl-extra help-mode easymenu cconv
cl-loaddefs pcase cl-lib epa-file epa derived epg epg-config disaster
generic generic-x time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan
thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote dbusbind inotify
dynamic-setting x multi-tty make-network-process emacs)

Memory information:
((conses 16 297179 14932)
  (symbols 48 28063 0)
  (miscs 40 107 370)
  (strings 32 48837 8668)
  (string-bytes 1 1295984)
  (vectors 16 43908)
  (vector-slots 8 786143 6898)
  (floats 8 265 274)
  (intervals 56 511 12)
  (buffers 976 23)
  (heap 1024 49084 1269))