Re: [libvirt] [PATCH] build: ask for -std=gnu99 explicitly

On Mon, Oct 07, 2019 at 15:09:52 +0100, Daniel Berrange wrote: > We previously got -std=gnu99 secretly enabled as a side-effect > of requesting the 'stdarg' gnulib module. We rely on some > extensions from c99/gnu99 and while RHEL-7 supports this, it > still defaults to gnu89. RHEL-7 also supports some newer > standards but declares them experimental/incomplete, so sticking > with gnu99 is best bet for now & matches historical usage. > > Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; > --- > m4/virt-compile-warnings.m4 | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4 > index f9460e82ba..502f7384ff 100644 > --- a/m4/virt-compile-warnings.m4 > +++ b/m4/virt-compile-warnings.m4 > @@ -189,6 +189,10 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[ > wantwarn="$wantwarn -Werror" > fi > > + # Request the gnu99 standard which is the best choice with > + # gcc 4.8.0 > + wantwarn="-std=gnu99" > + It feels odd to add this via the warning flags variable. I know this is a hack until we get rid of the old build system, but I think you should at least admit it in the commit message or comment that it's deliberate.