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

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

[ebuild  N     ] dev-lang/tk-8.6.17:0/8.6::gentoo  USE="threads truetype (-aqua) -debug -test -xscreensaver" 4486 KiB
[ebuild  N     ] dev-tcltk/tktreectrl-2.4.1-r1::gentoo  USE="threads -debug -shellicon -test" 923 KiB

Total: 2 packages (2 new), Size of downloads: 5409 KiB