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Date:   Mon, 11 Jan 2021 07:37:19 -0600
From:   Josh Poimboeuf <jpoimboe@redhat.com>
To:     Valdis =?utf-8?Q?Kl=C4=93tnieks?= <valdis.kletnieks@vt.edu>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Kees Cook <keescook@chromium.org>,
        linux-hardening@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] gcc-plugins: fix gcc 11 indigestion with plugins...
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On Mon, Jan 11, 2021 at 07:31:17AM -0500, Valdis Klētnieks wrote:
> On Mon, 11 Jan 2021 05:56:59 -0500, I said:
> 
> > > It's probably related. I'm just having a hard time understanding why 4.9 and 5.4
> > > whine about the lack of a space, while 8.3 and 11 didn't complain...
> 
> So after more digging, at least some clarity has surfaced.
> 
> It looks like it's not a kernel source tree issue, it's a g++ issue fixed in g++ 6 and later.
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69959
> 
> And it looks like there was an intent to backport it to 4.9 and 5.4:
> https://gcc.gnu.org/legacy-ml/gcc-patches/2016-02/msg01409.html
> 
> The bugtracker doesn't show an equivalent for 69959 being closed against 4.9.x or 5.[56],
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63254 has a patch for one of the
> gcc-supplied files that tosses the warning, but that way lies madness...
> 
> Not sure what we want to do here - the main alternatives I see are:
> 
> Tell people still using 4.9/5.4 to either live with the warning or upgrade to 6 or later
> 
> Make the flag a variable and pass either -std=gnu++98 or -std=gnu++11
> depending on the output of 'g++ --version'
> 
> What say the peanut gallery?

I think putting the flag in a variable (based on call cc-ifversion)
should be easy enough, then we can put this little saga behind us and
pretend it never happened :-)

-- 
Josh