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From:   David Laight <David.Laight@ACULAB.COM>
To:     =?windows-1257?Q?=27Valdis_Kl=E7tnieks=27?= 
        <valdis.kletnieks@vt.edu>, Kees Cook <keescook@chromium.org>
CC:     Josh Poimboeuf <jpoimboe@redhat.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        "linux-hardening@vger.kernel.org" <linux-hardening@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH RESEND] gcc-plugins: avoid errors with -std=gnu++11 on old
 gcc
Thread-Topic: [PATCH RESEND] gcc-plugins: avoid errors with -std=gnu++11 on
 old gcc
Thread-Index: AQHXG7xcElVT0YEvr0m/P+UnKynj6KqJn0dQ
Date:   Thu, 18 Mar 2021 11:41:29 +0000
Message-ID: <279b22592f1e43a48beeecd34e50b385@AcuMS.aculab.com>
References: <279558.1615192821@turing-police> <202103172251.F9D770D@keescook>
 <282490.1616047333@turing-police>
In-Reply-To: <282490.1616047333@turing-police>
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From: Valdis Kletnieks
> Sent: 18 March 2021 06:02
> 
> On Wed, 17 Mar 2021 22:52:56 -0700, Kees Cook said:
> > On Mon, Mar 08, 2021 at 03:40:21AM -0500, Valdis KlDtnieks wrote:
> > > It turns out that older gcc (4.9 and 5.4) have gnu++11 support, but
> > > due to a gcc bug fixed in gcc6, throw errors during the build.
> > > The relevant gcc bug is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69959
> > >
> > > Version the option based on what gcc we're using.
> >
> > Is there a better way to detect this than with version checking?
> 
> Not really.  gcc 11 needs --std=gnu++11 to build it.  And although
> gcc4 and gcc5 *claim* to support it, there's a known bug, so we *can't*
> feed gnu++11 to them.  We can check versions..

That gcc bug just implies you need a space after "xxx".
That is easily fixable in the sources.
Is there another problem?

(Apart from the standards committee breaking everything again.)

	David

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