emerge -u world
Calculating world dependencies \
!!! All ebuilds that could satisfy ">=gnome-extra/evolution-data-server-1.7" have been masked.
!!! One of the following masked packages is required to complete your request:
- gnome-extra/evolution-data-server-1.8.1-r1 (masked by: ~x86 keyword)
- gnome-extra/evolution-data-server-1.8.2 (masked by: ~x86 keyword)

For more information, see MASKED PACKAGES section in the emerge man page or
refer to the Gentoo Handbook.
(dependency required by "gnome-base/control-center-2.16.1" [ebuild])



!!! Problem resolving dependencies for gnome-base/gnome-vlos
!!! Depgraph creation failed.