Subject: Re: [PATCH bpf] selftests/bpf: Filter out _GNU_SOURCE when compiling test_cpp

From: Jakub Kicinski <[email-masked]>
Date: Fri, 26 Jul 2024 18:10:20 -0700

On Fri, 26 Jul 2024 17:45:06 -0700 Andrii Nakryiko wrote:
> or we could
> 
> #ifndef _GNU_SOURCE
> #define _GNU_SOURCE
> #endif
> 
> (though we have 61 places with that...) so as to not have to update
> every target in Makefile.

AFAIU we have -D_GNU_SOURCE= twice _in the command line args_ :(
One is from the Makefile which now always adds it to CFLAGS,
the other is "built-in" in g++ for some weird reason.

FWIW I have added this patch to the netdev "hack queue" so no
preference any more where the patch lands :)