bug#68213: 30.0.50; completion-preview-tests failure in --without-x build

[Eli Zaretskii]

> From: john muhl <jm@pub.pink>
> Cc: 68213@debbugs.gnu.org
> Date: Tue, 02 Jan 2024 16:49:15 -0600
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: john muhl <jm@pub.pink>
> >> Cc: 68213@debbugs.gnu.org
> >> Date: Tue, 02 Jan 2024 11:48:49 -0600
> >> 
> >> Eli Zaretskii <eliz@gnu.org> writes:
> >> 
> >> >> Date: Tue, 02 Jan 2024 10:42:59 -0600
> >> >> From:  john muhl via "Bug reports for GNU Emacs,
> >> >>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> >> >> 
> >> >> Running ‘make -k -C test check-lisp’ on master with a build
> >> >> configured without X produces the following error:
> >> >> 
> >> >>   cd emacs
> >> >>   ./autogen.sh
> >> >>   ./configure --without-x
> >> >>   make -j$(nproc)
> >> >>   make -k -C test check-lisp
> >> >>   …
> >> >>   In toplevel form:
> >> >>   lisp/completion-preview-tests.el:23:2: Error: Symbol's value
> >> >>   as variable is void: mouse-wheel-up-event
> >> >>   make[3]: *** [Makefile:159: lisp/completion-preview-tests.elc] Error 1
> >> >>   make[3]: Target 'lisp/completion-preview-tests.log' not remade 
> >> >> because of errors.
> >> >
> >> > Thanks, please try again, I hope I fixed this.
> >> 
> >> That removes the warnings during make
> >
> > I see error, not warning.
> >
> >> but unfortunately the test still fails with the same error.
> >
> > Which error?
> >
> > Please say
> >
> >   $ cd test && make lisp/completion-preview-tests.log
> >
> > and then post the part of the log with the full error message.
> 
>   $ cd test && make lisp/completion-preview-tests.log
>     ELC      lisp/completion-preview-tests.elc
> 
>   In toplevel form:
>   lisp/completion-preview-tests.el:23:2: Error: Symbol's value as
>   variable is void: mouse-wheel-up-event
>   make: *** [Makefile:159: lisp/completion-preview-tests.elc] Error 1
> 
>   $ cat lisp/completion-preview-tests.log
>   cat: lisp/completion-preview-tests.log: No such file or directory
> 
>   $ git rev-parse HEAD
>   0bc42eec9836d5f977d4187d57c829895726b862

I don't understand how that can happen when completion-preview.el has
these symbols defvar'ed.  Stefan, what am I missing here?