small patch for numactl. Comments?

[Larry McVoy]

On Tue, Nov 14, 2017 at 06:10:34PM +0100, Mateusz Guzik wrote:
> > I'm wacking LMbench to be numa aware and this patch would help me make
> > sure that when you are a numa machine you could insist that people 
> > run the benchmark via numactl (imma gonna blog about numa, it sucks
> > unless you are numa aware).
> > 
> 
> Well, I think the right thing to do is to query the existing policy and
> complain when it turns out nothing is set. Perhaps exit by default and
> add a switch to proceed anyway.

As already stated, that means #ifdef-ing portable code.  Not a fan of that.

I believe someone already approved env var approach anyway.