bug#33771: 27.0.50; Error building Harfbuzz branch on Debian testing

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Tue, 18 Dec 2018 16:06:48 +0100
> Cc: Mike Kupfer <mkupfer@alum.berkeley.edu>, 33771@debbugs.gnu.org, 
>       far.nasiri.m@gmail.com
> 
> We're down to 1 warning:
> 
>   CC       ftfont.o
> ftfont.c:482:1: warning: ‘ftfont_get_hb_font’ defined but not used
> [-Wunused-function]
>  ftfont_get_hb_font (struct ftfont_info *ftfont_info)
>  ^~~~~~~~~~~~~~~~~~

Should be fixed now.