When libnl is selected, libpcap links with it. Since libpcap doesn't
provide a .pc file and arp-scan doesn't use its libpcap-config script,
we must provide the additional options explicilty.
Fixes
http://autobuild.buildroot.net/results/c605c8cc36348f199a36e2652851b8d02ee222c0
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
