Re: [PATCH v2 1/1] git-compat-util: add a test balloon for C99 support

From: Jeff King <peff@peff.net>
Date: Nov 17, 2021, 02:58 UTC
Message-ID: <YZRvwfIaAODilQc3@coredump.intra.peff.net>
In-Reply-To: <YZRedzMSodOYjjPP@camp.crustytoothpaste.net>

On Wed, Nov 17, 2021 at 01:44:23AM +0000, brian m. carlson wrote:

Show 6 quoted lines

> > Do most compilers understand -std=gnu99? It seems like we're breaking
> > the out-of-the-box build for everything that isn't gcc or clang.
> 
> I'm pretty sure -Wall is GCC- and clang-specific, as is -Wl,-rpath, so I
> think we've already crossed that bridge.  There are places in
> config.mak.uname where they're specifically overridden for that reason.

That's a good point. I guess we don't really have good data on how many people will be (newly) affected either way.

Show 11 quoted lines

> > I understand that older versions of gcc (prior to 5.1.0, from my
> > digging) default to gnu89, and so they would be broken _without_ this.
> > So it is a tradeoff one way or the other. But somehow this seems
> > backwards to me. We should assume that modern compilers support C99 out
> > of the box, and put the burden on older ones to trigger C99 support in
> > whatever non-portable way they need.
> 
> We'll have to adjust the CI job that builds with GCC 4.8, but I can do
> that.  I just am not eager to hear complaints from people that it
> doesn't work out of the box, especially since CentOS 7 is going to hit
> this case.

Nor am I. I wonder if there's a way we can make it work out of the box everywhere. Using detect-compiler more widely would be one way to do that, though that's a bigger change to the Makefile in general. I kind of wonder if we could just assume in config.mak.uname that Linux will always have a compiler that understands -std=gnu99.

-Peff