These ebuilds come from http://github.com/sjnewbury/multilib-overlay.
If you have some problems, go to the official site first.
avahi : System which facilitates service discovery on a local network ( http://avahi.org/ )
c-ares : C library that resolves names asynchronously ( http://daniel.haxx.se/projects/c-ares/ )
libidn : Internationalized Domain Names (IDN) implementation ( http://www.gnu.org/software/libidn/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a multilib
For Paludis use this rsync : rsync://gentoo.zugaina.org/multilib-portage
If you have a problem : ycarus(-at-)zugaina.org