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

Calculating dependencies ... done!
Dependency resolution took 0.96 s (backtrack: 0/20).

[ebuild  N     ] games-emulation/libretro-bnes-0.0.1_pre20180723::gentoo  USE="-debug" 150 KiB

Total: 1 package (1 new), Size of downloads: 150 KiB