Re: master 02bca34: Utilize new string decoding feature in GTK native input

[Eli Zaretskii <eliz@gnu.org>]

> commit 02bca34852b1f9dd2b3e5364274452d377686f6a
> Author:     Po Lu <luangruo@yahoo.com>
> AuthorDate: Sat Feb 19 09:18:27 2022 +0800
> Commit:     Po Lu <luangruo@yahoo.com>
> CommitDate: Sat Feb 19 09:18:27 2022 +0800
> 
>     Utilize new string decoding feature in GTK native input
> 
>     * src/gtkutil.c (xg_im_context_commit): Don't decode strings
>     manually using g_utf8_to_ucs4 but pass unibyte string as the
>     keystroke event arg instead.

Is this a good idea?  Consing a string when we process input increases
GC pressure, and what issues does this change solve as a
counter-weight for that disadvantage?  Is g_utf8_to_ucs4 a problematic
API or something?  If so, we could use our own implementation
instead.  But in general, decoding UTF-8 encoded C string is better
done without consing a string and then using the coding.c stuff.
After all, if the original string is 100% guaranteed to be in UTF-8,
the decoding is almost trivial.