[PATCH v2] libctf: update regexp to allow makeinfo to build document

[Nick Alcock]

On 14 Jan 2023, Enze Li via Binutils verbalised:

> While trying to build gdb on latest openSUSE Tumbleweed, I noticed the
> following warning,
>
>  checking for makeinfo... makeinfo --split-size=5000000
>  configure: WARNING:
>  *** Makeinfo is too old. Info documentation will not be built.
>
> then I checked the version of makeinfo, it said,
> ======
> $ makeinfo --version
> texi2any (GNU texinfo) 7.0.1
>
> Copyright (C) 2022 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> ======
>
> After digging a little bit, it became quite obvious that a dot is
> missing in regexp that makes it impossible to match versions higher than
> 7.0, and here's the solution:
>
> -       | egrep 'texinfo[^0-9]*(6\.[3-9]|[7-9][0-9])' >/dev/null 2>&1; then
> +       | egrep 'texinfo[^0-9]*(6\.[3-9]|[7-9]\.[0-9])' >/dev/null 2>&1; then
>
> However, Eli pointed out that the solution above has another problem: it
> will stop working when Texinfo 10.1 will be released.  Meanwhile, he
> suggested to solve this problem permanently.  That is, we don't care
> about the minor version for Texinfo > 6.9, we only care about the major
> version.
>
> In this way, problem solved permanently, thanks to Eli.

Looks good to me: approved. (I can commit it if you like.)

This should probably also be backported to the 2.40 branch to keep the
latest released GNU tools building with the latest released GNU tools.