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

Calculating dependencies ...

!!! Problem resolving dependencies for =games-util/gamemode-1.8.2
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=games-util/gamemode-1.8.2" has unmet requirements.
- games-util/gamemode-1.8.2::gentoo USE="-elogind (-systemd)"

  The following REQUIRED_USE flag constraints are unsatisfied:
    exactly-one-of ( systemd elogind )