There is a newer version of the avahi patch with comments relating to this at:
https://sourceforge.net/tracker/index.php?func=detail&aid=1474791&group_id=8642&atid=308642 The patch also has the problem of failing to build if libavahi-compat-libdnssd-dev as it tries to build Bonjour (which is slightly broken) support instead of Avahi support.