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

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

[ebuild  N     ] x11-libs/libXcursor-1.2.3::gentoo  USE="-doc" 286 KiB
[ebuild  N     ] x11-libs/libXinerama-1.1.6::gentoo  USE="-doc" 263 KiB
[ebuild  N     ] media-libs/glfw-3.3.9::gentoo  USE="-wayland-only" 801 KiB

Total: 3 packages (3 new), Size of downloads: 1349 KiB