[Bug c/107954] Support -std=c23/gnu23 as aliases of -std=c2x/gnu2x

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107954

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2022-12-02
           Keywords|                            |diagnostic,
                   |                            |internal-improvement
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

The following options (and maybe some in the diagnostic messages too) need to
be changed/aliased:
Wc11-c2x-compat
std=c2x

Internally the macros:
D_C2X
STD_C2X
CLK_STDC2X
CLK_GNUC2X

the language name:
c-opts.cc:  lang_hooks.name = "GNU C2X";

And a few other places.
It is early in stage 4 of GCC 13 release cycle but I will leave it up to the C
maintainers to see if they want the change for GCC 13 or wait till stage 1 of
GCC 14.

Confirmed otherwise.