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

Calculating dependencies ... done!
Dependency resolution took 0.99 s (backtrack: 0/20).

[ebuild  N     ] app-eselect/eselect-unison-0.4::gentoo  0 KiB
[ebuild  N     ] dev-lang/ocaml-5.5.1:0/5.5.1::gentoo  USE="ocamlopt -emacs -flambda -latex -test -xemacs" 6457 KiB
[ebuild  N     ] net-misc/unison-2.53.7-r1:2.53::gentoo  USE="ocamlopt -doc -gui" 1380 KiB

Total: 3 packages (3 new), Size of downloads: 7836 KiB