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

Calculating dependencies ... done!
Dependency resolution took 1.02 s (backtrack: 0/20).

[ebuild   R    ] dev-build/ninja-1.13.2-r1::gentoo  USE="-doc -test" 286 KiB

Total: 1 package (1 reinstall), Size of downloads: 286 KiB