Re: Fix C23 compiler warning

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
>> Ah, yeah. That was 2.71 actually:
>> https://postgr.es/m/3838336.1657985206@sss.pgh.pa.us
>> 1.72 seems to have been released with some fixes from that one. Per
>> that thread, the related problem you noticed was with m4, and apparently
>> it was because macOS ships a version from 2006 (1.4.7). Here on Debian
>> bookworm I have m4 1.4.19; maybe macOS has updated its copy now?
>
> macOS hasn't gotten better:
>
> $ which m4
> /usr/bin/m4
> $ m4 --version
> GNU M4 1.4.6
> Copyright (C) 2006 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> It does seem like you-need-a-newer-m4 will be an issue for some folks,
> but given that you only need it to rebuild the configure script, maybe
> that will be a small enough set of people that we can cope. (In
> particular, the buildfarm wouldn't need updates.) On macOS, it's
> already pretty difficult to do useful development without any packages
> from MacPorts or Homebrew. MacPorts is shipping m4 1.4.19, and I'm
> sure Homebrew has something modern as well, so it's not like people
> would be forced to do their own builds on that platform.
>
> So maybe we should revive that idea, though I'd definitely target
> autoconf 2.72 not 2.71.

Just a data point: autoconf 2.72 came out under a year ago, so the most
recent Debian Stable (12) and Ubuntu LTS (24.04) only have 2.71.

If they stick to the the roughly-2-yearly cadence, Debian 13 will be out
before PostgreSQL 18, but the next Ubuntu LTS release isn't until April
2026.

They both have m4 1.4.19, though.

> regards, tom lane

- ilmari