bug#61049: 29.0.60; xfaces.c:font_maybe_unset_attribute unused in nox build

[Eli Zaretskii]

> Date: Wed, 25 Jan 2023 01:15:06 +0000
> From:  "Basil L. Contovounesios" via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Building emacs-29 --without-x emits the following warning:
> 
> xfaces.c:6021:1: warning: ‘font_maybe_unset_attribute’ defined but not used 
> [-Wunused-function]
>  6021 | font_maybe_unset_attribute (Lisp_Object font_object,
>       | ^~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Okay to fix on emacs-29, or not important enough?

Thanks, please install on the emacs-29 branch.