and finish the job. ncurses is now the only Makefile in the tree that
uses it since it wasn't a simple mechanical change, and will be
addressed in a future commit.
- Test that the basic socket options have the right defaults, that we can
change them, read them back, etc.
- Add and remove some multicast addresses.
- Send a loopback multicast address and make sure it arrives intact.
There's more that could be done here, but it's a start.
MFC after: 3 days