[Bug c/67479] Support for -Wformat-pedantic

["joseph at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67479

--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Mon, 7 Sep 2015, manu at gcc dot gnu.org wrote:

> 
> Index: c-format.c
> ===================================================================
> --- c-format.c  (revision 227095)
> +++ c-format.c  (working copy)
> @@ -1244,11 +1244,12 @@
>         return 0;
>      }
>    *format = fcp + 1;
> -  if (pedantic && !dollar_format_warned)
> +  if (warn_format_pedantic && !dollar_format_warned)
>      {
> -      warning (OPT_Wformat_, "%s does not support %%n$ operand number
> formats",
> -              C_STD_NAME (STD_EXT));
> -      dollar_format_warned = 1;
> +      dollar_format_warned =
> +       pedwarn (input_location, OPT_Wformat_pedantic,
> +                "%s does not support %%n$ operand number formats",
> +                C_STD_NAME (STD_EXT));

This should not be a pedwarn, because it only has undefined behavior in 
ISO C at runtime, not compile time.