bug#18610: 24.4.50; Specific file causing emacs to segfault upon opening

[Eli Zaretskii <eliz@gnu.org>]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: handa@gnu.org,  dmantipov@yandex.ru,  maden.ldm@gmail.com,  18610@debbugs.gnu.org
> Date: Fri, 03 Oct 2014 18:02:52 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Andreas Schwab <schwab@linux-m68k.org>
> >> Cc: Kenichi Handa <handa@gnu.org>,  dmantipov@yandex.ru,  maden.ldm@gmail.com,  18610@debbugs.gnu.org
> >> Date: Fri, 03 Oct 2014 17:16:27 +0200
> >> 
> >> Eli Zaretskii <eliz@gnu.org> writes:
> >> 
> >> > Btw, there's one more issue that bothers me.  In ONE_MORE_BYTE we have
> >> > this:
> >> >
> >> >     c = *src++;						\
> >> >     if (multibytep && (c & 0x80))			\
> >> >       {							\
> >> > 	if ((c & 0xFE) == 0xC0)				\
> >> > 	  c = ((c & 1) << 6) | *src++;			\
> >> > 	else						\
> >> > 	  {						\
> >> > 	    src--;					\
> >> > 	    c = - string_char (src, &src, NULL);	\
> >> > 	    record_conversion_result			\
> >> > 	      (coding, CODING_RESULT_INVALID_SRC);	\
> >> > 	  }						\
> >> >       }							\
> >> >
> >> > If 'src' is a signed type
> >> 
> >> It never is.
> >
> > You are right.  But c nevertheless does get assigned a negative value
> > when the byte at src is beyond 127, at least according to what GDB
> > shows me.
> 
> Exactly here:
> 	    c = - string_char (src, &src, NULL);

No, I meant here:

     c = *src++;						\