buildroot

package/netsniff-ng: allow to build with musl

netsniff-ng allows build with musl since version 0.5.8. With libnet
now being able to build with musl, let's enable musl for netsniff-ng
as well.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
[Thomas: update Config.in comment.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>