bug#20351: isearch-lax-whitespace should be customizable variable

[Ken T Takusagawa <kenta@mit.edu>]

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgment at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

M-x customize-variable
does NOT list isearch-lax-whitespace as a customizable variable

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/usr/share/emacs/24.3/etc/DEBUG.


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 14.04.2 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''

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  show-paren-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-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
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <right> <backspace> A <up> C-a <tab> <down> 
C-a <tab> <down> <tab> <down> <tab> <down> <tab> C-n 
<return> SPC SPC e l s e <return> SPC SPC SPC SPC <tab> 
e c h o SPC " C-a C-k <tab> e r r o r SPC 1 SPC " U 
n r e c o g n i z e d SPC o r i g i n a l SPC I S O 
" <return> <tab> f i <tab> C-r SPC SPC <up> <up> <up> 
<up> C-s SPC SPC C-s C-s C-s SPC C-g <up> <down> C-a 
C-s SPC SPC C-g C-g C-g <escape> x i n <backspace> 
s e r <tab> <backspace> a <tab> - t o <tab> l a <tab> 
<return> <up> <up> C-s SPC SPC <down> <down> C-s C-s 
C-s C-s <return> <backspace> C-x C-s C-h f i s e <tab> 
- t <tab> <backspace> t o <tab> l a <tab> <return> 
<up> C-h v i s e <tab> l a <tab> x - w h <tab> <return> 
<up> <up> <escape> x c u s t o <tab> i <tab> - v <tab> 
<return> i s e <tab> l a x - w h <tab> <tab> <tab> 
<tab> C-g C-g <help-echo> <help-echo> <down-mouse-1> 
<mouse-2> <down-mouse-1> <mouse-1> C-x 1 C-x 2 <escape> 
< C-s c u s C-s C-s C-s C-s C-s C-s C-s C-s C-s C-s 
C-s C-s C-s C-s C-s C-s C-s C-s C-s <up> C-s d e v 
<backspace> f v a r C-s C-s C-s C-s C-s C-s C-s <down> 
<down> <down> <down> <down> <down> <down> <down> <up> 
<right> <down-mouse-1> <mouse-1> ` x <down-mouse-1> 
<mouse-1> M-x r e p o <tab> r <tab> <return>

Recent messages:
Type "q" in help window to restore its previous buffer.
Making completion list...

Quit [2 times]
uncompressing isearch.el.gz...done
Note: file is write protected
Mark set
Mark saved where search started [2 times]
call-interactively: Buffer is read-only: #<buffer isearch.el.gz> [2 times]
Making completion list...

Load-path shadows:
/usr/share/emacs/24.3/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils jka-compr find-func cus-edit wid-edit help-mode
easymenu help-fns misearch multi-isearch vc-git sh-script smie
executable paren cus-start cus-load time-date tooltip ediff-hook
vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list newcomment lisp-mode register page
menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core frame cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote make-network-process dbusbind dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty emacs)