New port: net/mcjoin: Simple multicast testing application for UNIX

mcjoin is a very simple and easy-to-use tool to test IPv4 and IPv6
multicast. It features:

• an optional multicast generator (server)
• an end device that can act as a data sink (client)
• supports joining one or more groups:
  • ASM (*,G) support
  • SSM (S,G) support
• IPv4
• IPv6

WWW: https://github.com/troglobit/mcjoin

PR: 243787
Submitted by: John W. O'Brien <john@saltant.com>