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

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] acct-group/icinga-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-group/icingacmd-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-group/nagios-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/icinga-0-r3::gentoo  0 KiB

Total: 4 packages (4 new), Size of downloads: 0 KiB