From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: Noah Misch <noah@leadboat.com>, pgsql-hackers@postgresql.org
Subject: Re: Add -Wold-style-definition to CFLAGS?
In-reply-to: <20200609054708.52h6rdasqkjh32xv@alap3.anarazel.de>
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Comments: In-reply-to Andres Freund <andres@anarazel.de>
	message dated "Mon, 08 Jun 2020 22:47:08 -0700"
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Date: Tue, 09 Jun 2020 02:03:09 -0400
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Andres Freund <andres@anarazel.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.

> 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.

> 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.

			regards, tom lane