Use t for non-nil default values in boolean defcustom declarations

* lisp/emulation/viper-ex.el (ex-unix-type-shell):
* lisp/emulation/viper-init.el (viper-ms-style-os-p):
* lisp/eshell/em-glob.el (eshell-glob-case-insensitive):
* lisp/filecache.el (file-cache-ignore-case):
* lisp/lpr.el (lpr-add-switches):
* lisp/ls-lisp.el (ls-lisp-ignore-case):
* lisp/mail/binhex.el (binhex-use-external):
* lisp/progmodes/cperl-mode.el (cperl-electric-parens-mark):
Normalise default values to nil or t.

lisp/emulation/viper-ex.el

@@ -294,7 +294,8 @@
 	   "\\|"
 	   "bash$\\|bash.exe$"
 	   "\\)")
-	  shell-file-name)))
+	  shell-file-name)
+         t))
   "Is the user using a unix-type shell under a non-OS?"
   :type 'boolean)
 

lisp/emulation/viper-init.el

@@ -47,7 +47,8 @@
 (defun viper-window-display-p ()
   (and window-system (not (memq window-system '(tty stream pc)))))
 
-(defcustom viper-ms-style-os-p (memq system-type '(ms-dos windows-nt))
+(defcustom viper-ms-style-os-p
+  (not (not (memq system-type '(ms-dos windows-nt))))
   "Non-nil if Emacs is running under an MS-style OS: MS-DOS, or MS-Windows."
   :type 'boolean
   :tag "Is it Microsoft-made OS?"

lisp/eshell/em-glob.el

@@ -79,7 +79,7 @@ by zsh for filename generation."
   :type 'boolean
   :group 'eshell-glob)
 
-(defcustom eshell-glob-case-insensitive (eshell-under-windows-p)
+(defcustom eshell-glob-case-insensitive (not (not (eshell-under-windows-p)))
   "If non-nil, glob pattern matching will ignore case."
   :type 'boolean
   :group 'eshell-glob)

lisp/filecache.el

@@ -213,7 +213,7 @@ Defaults to the value of `case-fold-search'."
   :type 'boolean)
 
 (defcustom file-cache-ignore-case
-  (memq system-type '(ms-dos windows-nt cygwin))
+  (not (not (memq system-type '(ms-dos windows-nt cygwin))))
   "Non-nil means ignore case when checking completions in the file cache.
 Defaults to nil on DOS and Windows, and t on other systems."
   :type 'boolean)

lisp/lpr.el

@@ -73,7 +73,8 @@ switch on this list.
 See `lpr-command'."
   :type '(repeat (string :tag "Argument")))
 
-(defcustom lpr-add-switches (memq system-type '(berkeley-unix gnu/linux))
+(defcustom lpr-add-switches
+  (not (not (memq system-type '(berkeley-unix gnu/linux))))
   "Non-nil means construct `-T' and `-J' options for the printer program.
 These are made assuming that the program is `lpr';
 if you are using some other incompatible printer program,

lisp/ls-lisp.el

@@ -101,7 +101,7 @@ update the dependent variables."
   :group 'ls-lisp)
 
 (defcustom ls-lisp-ignore-case
-  (memq ls-lisp-emulation '(MS-Windows MacOS))
+  (not (not (memq ls-lisp-emulation '(MS-Windows MacOS))))
   "Non-nil causes ls-lisp alphabetic sorting to ignore case."
   :set-after '(ls-lisp-emulation)
   :type 'boolean

lisp/mail/binhex.el

@@ -49,7 +49,7 @@ input and write the converted data to its standard output."
   :type '(repeat string))
 
 (defcustom binhex-use-external
-  (executable-find binhex-decoder-program)
+  (not (not (executable-find binhex-decoder-program)))
   "Use external binhex program."
   :version "22.1"
   :type 'boolean)

lisp/progmodes/cperl-mode.el

@@ -275,7 +275,7 @@ Can be overwritten by `cperl-hairy' if nil."
   :type '(choice (const null) boolean)
   :group 'cperl-affected-by-hairy)
 
-(defcustom cperl-electric-parens-mark window-system
+(defcustom cperl-electric-parens-mark (not (not window-system))
   "Not-nil means that electric parens look for active mark.
 Default is yes if there is visual feedback on mark."
   :type 'boolean