1- RTFM
http://www.funtoo.org/Local_Overlay
2- Get this overlay:
# mkdir -p /var/overlay ; cd /var/overlay
# git clone https://github.com/coffnix/lizardfs-funtoo-overlay.git
3- Configure /etc/make.conf:
# echo 'PORTDIR_OVERLAY="/var/overlay/lizardfs-funtoo-overlay"' >> /etc/make.conf
4- Update your database:
# emerge app-portage/eix
# eix-update
5- Compile Lizarfs:
# emerge sys-cluster/lizardfs