bug#59544: [PATCH] Fixed lib-src/etags.c command execute vulnerability

[Eli Zaretskii]

> Date: Sun, 27 Nov 2022 01:03:10 +0800
> Cc: stefankangas@gmail.com, 59544@debbugs.gnu.org
> From: lux <lx@shellcodes.org>
> 
> I'm going to add the xxx parameter. If it is true, the line break will 
> be kept. Is this logic consistent with what you expressed? thank you 
> very much.

Much simpler:

static ptrdiff_t
readline_internal (linebuffer *lbp, FILE *stream, char const *filename, bool 
leave_cr)
{
 [...]
      if (c == '\n')
        {
          if (!leave_cr && p > buffer && p[-1] == '\r')
            {
 [...]

IOW, when this flag is TRUE, don't process \r specially.

Thanks.