These ebuilds come from https://github.com/regen2/regen2-overlay.
If you have some problems, go to the official site first.
e4rat : Toolset to accelerate the boot process and application startup ( http://e4rat.sourceforge.net/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a regen2-overlay
For Paludis use this rsync : rsync://gentoo.zugaina.org/regen2-overlay-portage
If you have a problem : ycarus(-at-)zugaina.org