bug#11503: 24.0.96; `defvaralias' doc string and alias name not respected by Customize

[Drew Adams]

(defcustom foo  t
  "Non-nil means foo it."
  :type 'boolean :group 'convenience)
 
(defvaralias 'bar 'foo
  "Non-nil means bar it.")
 
`C-h v bar' correctly says that bar is an alias for foo.  And it shows
the doc string for bar and provides a link to the doc string for foo.
It is clear to users what is going on.
 
`M-x customize bar' shows only the same thing as `M-x customize foo'.
 
Like `C-h v', customizing bar should (a) show the correct var name
(bar), (b) mention that it is an alias for foo, and (c) show bar's doc
string.  The mention of foo should include a link to foo's doc.  IOW,
same info that `C-h v' provides.
 
Being able to alias a variable in library toto, with prefix `toto-', to
a user option in library titi, with prefix `titi-', can be helpful for
users.  It can present them with not only a more relevant option name
for library toto, but also more relevant doc.  It can give them a toto
view of the variable.
 
The variable behavior can be described at different levels.  And the
behavior for library toto can be more complex - that is, the variable
value (which is obviously the same) can have toto-specific consequences.
For toto, the variable might do something additional.
 
Yes, it's the same variable/value in the end.  But speaking about it in
toto terms can be more accurate or more meaningful to a user of library
toto.
 

In GNU Emacs 24.0.96.1 (i386-mingw-nt5.1.2600)
 of 2012-04-28 on MARVIN
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.6) --no-opt --enable-checking --cflags
 -ID:/devel/emacs/libs/libXpm-3.5.8/include
 -ID:/devel/emacs/libs/libXpm-3.5.8/src
 -ID:/devel/emacs/libs/libpng-dev_1.4.3-1/include
 -ID:/devel/emacs/libs/zlib-dev_1.2.5-2/include
 -ID:/devel/emacs/libs/giflib-4.1.4-1/include
 -ID:/devel/emacs/libs/jpeg-6b-4/include
 -ID:/devel/emacs/libs/tiff-3.8.2-1/include
 -ID:/devel/emacs/libs/gnutls-3.0.9/include'