miramis ~ # emerge -1uavDN system

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

Calculating dependencies... done!
[ebuild     U  ] dev-lang/perl-5.18.2:0/5.18 [5.16.3:0/5.16] USE="berkdb doc gdbm ithreads -debug" 0 kB
[ebuild     U  ] sys-apps/man-pages-3.63 [3.62] USE="nls" LINGUAS="de -da -fr -it -ja -nl -pl -ro -ru -zh_CN" 0 kB
[ebuild     U  ] net-misc/openssh-6.6_p1-r1 [6.5_p1-r1] USE="X hpn pam tcpd -X509 -bindist -kerberos -ldap -ldns -libedit (-selinux) -skey -static" 0 kB

Total: 3 packages (3 upgrades), Size of downloads: 0 kB

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

dev-lang/perl:0

  (dev-lang/perl-5.18.2:0/5.18::gentoo, ebuild scheduled for merge) pulled in by
    =dev-lang/perl-5.18* required by (virtual/perl-parent-0.228:0/0::gentoo, installed)
    ^              ^^^^^                                                                                                                      
    (and 6 more with the same problem)

  (dev-lang/perl-5.16.3:0/5.16::gentoo, installed) pulled in by
    dev-lang/perl:0/5.16=[-build(-)] required by (dev-perl/IO-HTML-1.00.0:0/0::gentoo, installed)
                 ^^^^^^^^                                                                                                            
    =dev-lang/perl-5.16* required by (virtual/perl-digest-base-1.170.0-r1:0/0::gentoo, installed)
    ^              ^^^^^                                                                                                                                
    (and 26 more with the same problems)


It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously.  If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously. You may want to try a larger value of
the --backtrack option, such as --backtrack=30, in order to see if
that will solve this conflict automatically.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.


!!! The following installed packages are masked:
- media-gfx/kgraphviewer-2.1.1::gentoo (masked by: package.mask)
/usr/portage/profiles/package.mask:
# Michael Palimaka <kensington@gentoo.org> (26 Feb 2014)
# Doesn't build with recent graphviz. Dead upstream.
# Masked for removal in 30 days. Bug #491760.

For more information, see the MASKED PACKAGES section in the emerge
man page or refer to the Gentoo Handbook.

miramis ~ #