bug#18059: 24.3.92; defvar and special variables

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

> >> Not to mention lots of vacuous defvars to quiet the byte-compiler:
> >>
> >> (unless (> emacs-major-version 22)
> >>   (defvar display-buffer-reuse-frames))
> >
> > So here, what is the use of putting it below the toplevel? Why don't
> > you just write
> >
> > (defvar display-buffer-reuse-frames) ; For Emacs 22 and earlier.
> 
> Hey Drew, I am actually interested in your answer to this question,
> sorry if it came across as rhetorical.

I didn't take it wrong, Noam; don't worry.

I don't have a good answer, in terms of "I _need_ to do it this
way because otherwise...".

My arguments:

1. Some users _will_ do it this way.  Nothing says they shouldn't.
   If that means they lose out on some functionality then they will
   need to know that.  And some users will have already done it,
   so they will need to change.

   Is that really necessary?  Should it be?  What's the real need
   here?

2. As one user, I _prefer_ to do it the way I do it, for facility
   of code maintenance, i.e., to document to myself which versions
   need what.  Yes, I could do that using only comments (but I find
   this way clearer, as it's the same way I do it where it really
   matters).

HTH - D.