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

Calculating dependencies ... done!
Dependency resolution took 0.84 s (backtrack: 0/20).


!!! All ebuilds that could satisfy "=games-fps/duke3d-data-1.0-r6" have been masked.
!!! One of the following masked packages is required to complete your request:
- games-fps/duke3d-data-1.0-r6::gentoo (masked by: DUKE3D license(s))
A copy of the 'DUKE3D' license is located at '/Volumes/Disk 1/Repository/portage-git/licenses/DUKE3D'.


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