Run as root
layman -a unity-gentoo
layman -S
Then select the vivid
unity-gentoo profile:
# eselect profile list
Available profile symlink targets:
[1] default/linux/amd64/13.0
[2] default/linux/amd64/13.0/selinux
[3] default/linux/amd64/13.0/desktop
[4] default/linux/amd64/13.0/desktop/gnome
[5] default/linux/amd64/13.0/desktop/gnome/systemd
[6] default/linux/amd64/13.0/desktop/kde
[7] default/linux/amd64/13.0/desktop/kde/systemd
[8] default/linux/amd64/13.0/developer
[9] default/linux/amd64/13.0/no-multilib
[10] default/linux/amd64/13.0/x32
[11] hardened/linux/amd64
[12] hardened/linux/amd64/selinux
[13] hardened/linux/amd64/no-multilib
[14] hardened/linux/amd64/no-multilib/selinux
[15] hardened/linux/amd64/x32
[16] hardened/linux/uclibc/amd64
[17] hardened/linux/musl/amd64
[18] unity-gentoo:vivid/amd64 *
[19] unity-gentoo:utopic/amd64
When that is complete run the following to setup the correct package masking.
emerge -aqv unity-build-env
When that is complete run
emerge -uDNvta unity-meta
Thanks to many on Gentoo forums