Re: [PATCH 1/5] CodingGuidelines: update for C99

> Since 7bc341e21b5 (git-compat-util: add a test balloon for C99
> support, 2021-12-01) we've had a hard dependency on C99, but the prose
> in CodingGuidelines was written under the assumption that we were
> using C89 with a few C99 features.
>
> As the updated prose notes we'd still like to hold off on novel C99
> features, but let's make it clear that we target that C version, and
> then enumerate new C99 features that are safe to use.
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  Documentation/CodingGuidelines | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
> index 9fca21cc5f9..386ca0a0d22 100644
> --- a/Documentation/CodingGuidelines
> +++ b/Documentation/CodingGuidelines
> @@ -204,10 +204,14 @@ For C programs:
>     by e.g. "echo DEVELOPER=1 >>config.mak".
>  
>   - We try to support a wide range of C compilers to compile Git with,
> -   including old ones.  You should not use features from newer C
> +   including old ones.  As of Git v2.35.0 Git requires C99 (we check
> +   "__STDC_VERSION__"). You should not use features from a newer C
>     standard, even if your compiler groks them.
>  
> -   There are a few exceptions to this guideline:
> +   New C99 features have been phased in gradually, if something's new
> +   in C99 but not used yet don't assume that it's safe to use, some
> +   compilers we target have only partial support for it. These are
> +   considered safe to use:
>  
>     . since early 2012 with e1327023ea, we have been using an enum
>       definition whose last element is followed by a comma.  This, like