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

Calculating dependencies ... done!
Dependency resolution took 1.50 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/skalibs-2.15.0.0:0/2.15.0::gentoo  262 KiB
[ebuild  N     ] dev-lang/execline-2.9.9.1:0/2.9.0::gentoo  117 KiB
[ebuild  N     ] sys-apps/s6-2.15.0.0:0/2.15::gentoo  USE="execline" 271 KiB
[ebuild  N     ] sys-apps/s6-linux-init-1.2.0.1:0/1.2::gentoo  USE="sysv-utils" 66 KiB
[blocks B      ] sys-apps/sysvinit ("sys-apps/sysvinit" is soft blocking sys-apps/s6-linux-init-1.2.0.1)

Total: 4 packages (4 new), Size of downloads: 715 KiB
Conflict: 1 block (1 unsatisfied)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (sys-apps/sysvinit-3.15:0/0::gentoo, installed) pulled in by
    >=sys-apps/sysvinit-2.86-r6 required by (sys-apps/openrc-0.63-r1:0/0::gentoo, installed) USE="netifrc pam sysvinit unicode -audit -bash -debug -newnet -s6 (-selinux) -sysv-utils"

  (sys-apps/s6-linux-init-1.2.0.1:0/1.2::gentoo, ebuild scheduled for merge) pulled in by
    =sys-apps/s6-linux-init-1.2.0.1


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

https://wiki.gentoo.org/wiki/Handbook:X86/Working/Portage#Blocked_packages