[ECOS] Fix for OpenBSD stack

[Andrew Lunn]

On Mon, Sep 22, 2003 at 04:35:12PM +0200, Christoph Csebits wrote:
> hallo,
> 
> if using the "old" stack the macro IF_IS_EMPTY is not 
> defined, but is used in io/eth/current/src/net/eth_drv.c.
> 
> This patch should help

One of our guys noticed this recently as well, but i hadn't had time
to investigate. I will commit this soon as i find a free 10 minutes.

   Thanks
        Andrew