Re: Add -Wold-style-definition to CFLAGS?

Hi,

On 2020-06-09 02:03:09 -0400, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > Unfortunately it turns out that our CFLAG configure tests don't reliably
> > work with -Wold-style-definition. The problem is that the generated
> > program contains 'int main() {...}', which obviously is an old-style
> > definition. Which then causes a warning, which in turn causes the cflag
> > tests to fail because we run them with ac_c_werror_flag=yes.
>
> Ugh. I suspect main() might not be the only problem, either.

There's a few more, but they're far far less noisy. And I don't think
any change the results after the fix, because they don't check for
output on stderr (based on grepping through configure).

> > Upstream autoconf has fixed this in 2014 (1717921a), but since they've
> > not bothered to release since then...
>
> I wonder if there's any way to light a fire under them.

There's been talk about working towards a release a few months back:
https://lists.gnu.org/archive/html/autoconf/2020-03/msg00003.html

> > The easiest way that I can see to deal with that is to simply redefine
> > the relevant autoconf macro. For me that solves the vast majority of
> > these bleats in config.log. That's not particularly pretty, but we have
> > precedent for it... Since it's just 16 lines, I think we can live with
> > that?
>
> I don't really think that -Wold-style-definition is worth that.

Well, we don't need it for that, strictly speaking. Just using
AC_LANG_SOURCE is enough...

Greetings,

Andres Freund