Re: doc elisp intro cross reference fixes

[Richard Stallman]

    Indeed:  (defalias 'set-variable 'customize-set-variable)

    Note that if you mean this literally, this is a non-trivial change in
    as far as prefix arguments are concerned.  Right now, C-u set-variable
    will set the buffer-local value.

Yes, we would want to add a similar C-u feature to customize-set-variable
before doing this.

       Indeed.  We'd just need to make (defvar a b "*c") equivalent
       to (defcustom a b "c").

    You make this sound a lot simpler than it would be.  This will have to
    be handled individually and very carefully for each *-defvar, a huge
    amount of work.

In the long run, we want to do that huge amount of work.
All of these variables should have appropriate custom types.
That is already on the agenda of work that should be done.

However, in the short run, we don't have to do this immediately.  It is
certainly possible to handle all defvars with * using a default custom type
that allows all Lisp objects as values.  That loses nothing compared with
the way things are now.

      If an author decided to use a *-defvar instead of a
    defcustom, there probably is a good reason why he decided not to use a
    defcustom.

I think the most common reason would be that the Lisp package is old.

      For instance, default-enable-multibyte-characters has a
    *-defvar.  You do not want to turn this into a defcustom, because it
    would duplicate the defcustom for enable-multibyte-characters, which
    also sets the default value.  That would be extremely confusing to the
    Custom user.

We could do something special for cases like these.