$ emerge -puvD world

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

Calculating world dependencies /
!!! All ebuilds that could satisfy ">=x11-drivers/xf86-video-vesa-1.1.0" have been masked.
!!! One of the following masked packages is required to complete your request:
- x11-drivers/xf86-video-vesa-1.2.0 (masked by: missing keyword)
- x11-drivers/xf86-video-vesa-1.2.2 (masked by: missing keyword)
- x11-drivers/xf86-video-vesa-1.2.1 (masked by: missing keyword)

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


!!! Problem resolving dependencies for sys-apps/portage
!!! Depgraph creation failed.


$ emerge -uvNDp world

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

Calculating world dependencies \
emerge: there are no ebuilds to satisfy ">=dev-python/pyxmms-2.02".
(dependency required by "media-sound/ipodder-2.0_rc4" [ebuild])



!!! Problem resolving dependencies for media-sound/ipodder
!!! Depgraph creation failed.