[committed, wwwdocs] gcc-11/changes: Add notes about column number changes

[Lewis Hyatt]

On Tue, Oct 6, 2020 at 11:09 AM David Malcolm <dmalcolm@redhat.com> wrote:
>
> I've taken the liberty of pushing this website patch, having checked
> that it validates.
>
> It covers the changes by Lewis in 004bb936d6d5f177af26ad4905595e843d5665a5
> (PR 49973 and PR 86904).
>

Cool, thank you for mentioning it here! Sorry if that's something I
was supposed to include with the original patch...
BTW, one small note:

> +      Additionally, in previous releases of GCC, tab characters in the source
> +      would be emitted verbatim when quoting source code, but be prefixed
> +      with whitespace or line number information, leading to misalignments
> +      in the resulting output when compared with the actual source.  Tab
> +      characters are now printed as an appropriate number of spaces, using the
> +      <a href="https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html#index-ftabstop">-ftabstop</a>
> +      option (which defaults to 8 spaces per tab stop).
> +    </p>
> +  </li>
>  </ul>

In previous versions, a tab was output as a single space, not an
actual tab character, so it led to misalignment even without any
prefix, FWIW.

-Lewis