eix is a indexing tool for Gentoo's portage or as they call it a "Small utility for searching ebuilds with indexing for fast results"

layman is a portage overlay manager, adding extra (custom or user) ebuilds to the ones of Gentoo.

Now wouldn't it be nice if those two can work together, making it possible to search and index the added overlays.Well, by default it doesn't. It looks like eix can't understand layman's entry :

source /usr/portage/local/layman/make.conf

To fix this, have layman add the overlay entries directly into /etc/make.conf by changing the make_conf entry in /etc/layman/layman.cfg like this

make_conf : /etc/make.conf

Now your update-eix will find the newly added overlays and start indexing them. Happy searching!