These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! All ebuilds that could satisfy "=games-arcade/oshu-2.0.3" have been masked.
!!! One of the following masked packages is required to complete your request:
- games-arcade/oshu-2.0.3::gentoo (masked by: CC-BY-NC-4.0 license(s))
A copy of the 'CC-BY-NC-4.0' license is located at '/Volumes/Disk 1/Repository/portage-git/licenses/CC-BY-NC-4.0'.


For more information, see the MASKED PACKAGES section in the emerge
man page or refer to the Gentoo Handbook.