These ebuilds come from https://github.com/anyc/steam-overlay.
If you have some problems, go to the official site first.
steam-runtime-udev : Linux dynamic and persistent device naming support (aka userspace devfs) ( http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev.html )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a steam
For Paludis use this rsync : rsync://gentoo.zugaina.org/steam-portage
If you have a problem : ycarus(-at-)zugaina.org