Completing this guide, here is what you need to do in order to be able to login/su by using your fingerprint.
The fingerprint used on the example, is an authentec aes2501 on a hp pavilion 6520ea.
Create a new gentoo overlay (/usr/local/portage/fprint), add it to portage, get the ebuilds, and install:
cd /usr/local/portage/fprint
kdir -p media-libs/libfprint
mkdir -p sys-auth/pam_fprint
mkdir -p […]