tatsh-overlay
This is stuff I make randomly. If you find a bug, please file an issue.
Installation
emerge app-eselect/eselect-repository
eselect repo enable tatsh-overlay
emerge --syncOnly unmask packages you use from this repository
Based on Masking installed but unsafe ebuild repositories.
In /etc/portage/package.mask/tatsh-overlay:
*/*::tatsh-overlay
In /etc/portage/package.unmask/tatsh-overlay (example):
games-arcade/stepmania::tatsh-overlay