Re: `texinfo.tex` doesn't work with xetex

[Gavin Smith]

On Sat, Aug 20, 2022 at 07:26:37PM +0000, Werner LEMBERG wrote:
> 
> [texinfo version 2022-08-20.18]
> 
> 
> >> I've had another look at and I've fixed it, so @U can be used for
> >> ASCII characters once again.
> >
> > Thanks for the quick fix.
> 
> I said this too early :-)
> 
> 
> This code
> 
> ```
> \input texinfo.tex
> 
> @documentencoding UTF-8
> 
> @macro foo{bar-baz}
> \bar-baz\
> @end macro
> 
> @foo{xxx}
> 
> @bye
> ```
> 
> compiled with `PDFTEX=xetex texi2pdf` fails with
> 
> ```
> Missing @endcsname inserted.
> <to be read again>
>                    @char
> -->@ifpassthroughchars -@else @char
>                                     "2D @fi

Oh dear.  I've fixed it now.  I've made it so that \DeclareUnicodeCharacter
leaves active definitions of ASCII characters alone.  Evidently the active
definition of hyphen was already correct but \DeclareUnicodeCharacter broke
it.