bug#12717: 24.2.50; [PATCH] `imenu--split-submenus' incorrectly distinguishes submenus

["Drew Adams" <drew.adams@oracle.com>]

Imenu allows the use of something it calls "special" menu elements,
which have this form: (INDEX-NAME POSITION FUNCTION ARGUMENTS...)
 
`imenu--split-submenus' needs to distinguish submenus from ordinary menu
elements, including from special menu elements.  Currently this is
bugged.
 
The current code for `imenu--split-submenus' does this:
 
(defun imenu--split-submenus (alist)
  "..."
  (mapcar (lambda (elt)
            (if (and (consp elt) (stringp (car elt)) (listp (cdr elt)))
                (imenu--split-menu (cdr elt) (car elt))
              elt))
   alist))
 
The `if' condition should instead test whether the element is a submenu.
We have a function that does that: `imenu--subalist-p'.  I believe this
is the correct code:
 
(defun imenu--split-submenus (alist)
  "..."
  (mapcar (lambda (elt)
            (if (imenu--subalist-p elt)
                (imenu--split-menu (cdr elt) (car elt))
              elt))
   alist))

In GNU Emacs 24.2.50.1 (i386-mingw-nt5.1.2600)
 of 2012-10-22 on DANI-PC
Bzr revision: 110618 monnier@iro.umontreal.ca-20121022132928-232zm0fecassmhfb
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.7) --no-opt --enable-checking --cflags
 -I../../libs/libxpm-3.5.8/include -I../../libs/libxpm-3.5.8/src
 -I../../libs/libpng-1.4.10 -I../../libs/zlib-1.2.6
 -I../../libs/giflib-4.1.4-1/include -I../../libs/jpeg-6b-4/include
 -I../../libs/tiff-3.8.2-1/include
 -I../../libs/libxml2-2.7.8-w32-bin/include/libxml2
 -I../../libs/gnutls-3.0.16/include
 -I../../libs/libiconv-1.14-2-mingw32-dev/include'