print link-layer addresses (on MacOS)
print link-layer addresses (on MacOS)

The link-layer addresses are now printed-out, for MacOS anyhow.  On
Linux, the link-layer seems to be under a different address family.

This difference also means I'm going to have to do #ifdefs by platform.
Yeuch.  I'd had enough of that in my days porting device drivers...

pdelong42/pcap-sandbox