List nlcrtl families

What it this thing

This program prints all the famlies currently registered to nlctrl and their multicast groups. It was a nice exercise in netling, generic netlink and generally linux and C stuff that I forgot after years working on other platforms. The output is similiar to installing libnl-utils and running genl-ctrl-list -d

Main sources:

• https://stackoverflow.com/questions/18062268/using-nl80211-h-to-scan-access-points
• https://www.infradead.org/~tgr/libnl/