[blocks B     ] net-dns/avahi (is blocking net-misc/mDNSResponder-107.6-r5)
[blocks B     ] kde-misc/kdnssd-avahi (is blocking kde-base/kdelibs-3.5.8-r10)
[blocks B     ] x11-misc/xkbdata (is blocking x11-misc/xkeyboard-config-1.1)
[blocks B     ] >=sys-apps/util-linux-2.13_pre (is blocking sys-process/scheduti
ls-1.5.0)
[blocks B     ] <media-libs/openexr-1.5.0 (is blocking media-libs/ilmbase-1.0.0)
[blocks B     ] dev-util/portatosourceview (is blocking app-portage/portato-0.8.
6.2)
[blocks B     ] x11-misc/xkeyboard-config (is blocking x11-misc/xkbdata-1.0.1)
[blocks B     ] net-misc/mDNSResponder (is blocking net-dns/avahi-0.6.18, net-dn
s/avahi-0.6.21)
[blocks B     ] <sys-apps/baselayout-2.0.0_rc (is blocking sys-apps/makedev-3.23
.1)
[blocks B     ] sys-process/schedutils (is blocking sys-apps/util-linux-2.13-r2)
[blocks B     ] app-crypt/libgssapi (is blocking net-libs/libgssglue-0.1)

Total: 818 packages (518 upgrades, 3 downgrades, 233 new, 7 in new slots, 57 rei
nstalls, 11 blocks), Size of downloads: 1,178,075 kB
Portage tree and overlays:
 [0] /usr/portage
 [1] /usr/portage/local/layman/sabayon

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

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

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked