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

Calculating dependencies ... done!
Dependency resolution took 1.00 s (backtrack: 0/20).

[ebuild  N     ] sys-process/lsof-4.99.7::gentoo  USE="rpc (-selinux)" 1129 KiB
[ebuild  N     ] app-forensics/rkhunter-1.4.6-r2::gentoo  USE="(-selinux)" 303 KiB

Total: 2 packages (2 new), Size of downloads: 1431 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by app-forensics/rkhunter-1.4.6-r2::gentoo
# required by =app-forensics/rkhunter-1.4.6-r2 (argument)
>=sys-process/lsof-4.99.7 rpc