emerge -uDpv world

These are the packages that I would merge, in order:

Calculating world dependencies \
!!! All ebuilds that could satisfy ">=sys-kernel/linux-headers-2.6.5" have been masked.
!!! One of the following masked packages is required to complete your request:
- sys-kernel/linux-headers-2.6.8.1-r2 (masked by: profile)
- sys-kernel/linux-headers-2.6.11 (masked by: profile, -* keyword)
- sys-kernel/linux-headers-2.6.8.1-r4 (masked by: profile, ~x86 keyword)

For more information, see MASKED PACKAGES section in the emerge man page or
section 2.2 "Software Availability" in the Gentoo Handbook.
!!!    (dependency required by "sys-libs/glibc-2.3.4.20041102-r1" [ebuild])


!!! Problem with ebuild sys-libs/zlib-1.2.2
!!! Possibly a DEPEND/*DEPEND problem.

!!! Depgraph creation failed.