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

Calculating dependencies ...

!!! Problem resolving dependencies for =x11-apps/igt-gpu-tools-2.3
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=x11-apps/igt-gpu-tools-2.3" has unmet requirements.
- x11-apps/igt-gpu-tools-2.3::gentoo USE="X -chamelium -man -overlay -runner -tests -unwind -valgrind -xv" VIDEO_CARDS="-amdgpu -intel -nouveau"

  The following REQUIRED_USE flag constraints are unsatisfied:
    any-of ( video_cards_amdgpu video_cards_intel video_cards_nouveau )

  The above constraints are a subset of the following complete expression:
    any-of ( video_cards_amdgpu video_cards_intel video_cards_nouveau ) overlay? ( video_cards_intel any-of ( X xv ) ) runner? ( tests )