Re: master a539488: Always make a multibyte string for the frame title (bug#42904)

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Sun, 23 Aug 2020 20:41:35 +0200
> Cc: Mattias Engdegård <mattiase@acm.org>
> 
> This is giving me some compilation warnings on Debian:
> 
> xdisp.c: In function ‘gui_consider_frame_title’:
> xdisp.c:12571:31: warning: pointer targets in passing argument 1 of 
> ‘str_as_multibyte’ differ in signedness [-Wpointer-sign]
> 12571 |       len = str_as_multibyte (title, mode_line_noprop_buf_end - title,
>       |                               ^~~~~
>       |                               |
>       |                               char *
> In file included from dispextern.h:25,
>                  from composite.h:29,
>                  from xdisp.c:441:
> character.h:226:36: note: expected ‘unsigned char *’ but argument is of type 
> ‘char *’
>   226 | CHAR_STRING (int c, unsigned char *p)
>       |                     ~~~~~~~~~~~~~~~^

Silly compiler.  Please try again, I hope I fixed this.