bug#16744: 24.3.50; REGRESSION: C-h v does not show doc for `ediff-highlight-all-diffs'

[Eli Zaretskii]

> Date: Fri, 14 Feb 2014 05:43:45 -0500
> From: Michael Kifer <michael.kifer@stonybrook.edu>
> CC: "16744@debbugs.gnu.org" <16744@debbugs.gnu.org>
> 
>     This problem is caused by some change in the emacs compiler.
>     The reason I was not seeing it is because I was using .elc files of
>     my development copy of ediff, which were compiled with an older
>     version of emacs. With those .elc's the documentation string was
>     being shown.
> 
>     Perhaps the empty doc-string in defvar now zaps the doc-string
>     specified in the preceding defcustom while previously it didn't? If
>     so, the previous behavior was smarter.

But why do we need both the defcustom and the defvar in the macro?