winhost win # emerge -uDNav world

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

Calculating world dependencies... done!
[blocks B     ] =sys-devel/gcc-3.3* (is blocking app-emulation/emul-linux-x86-compat-1.0-r3)
[ebuild  NS   ] sys-devel/gcc-3.3.6-r1  USE="fortran gtk nls (-altivec) -bootstrap -boundschecking -build -doc -gcj (-hardened) -ip28 -ip32r10k (-multilib) -multislot (-n32) (-n64) -nocxx -nopie -nossp -objc -test -vanilla" 0 kB 
[ebuild     U ] sys-apps/hal-0.5.7.1-r5 [0.5.7.1-r4] USE="crypt -acpi -debug -dmi -doc -pcmcia (-selinux)" 0 kB 

Total: 2 packages (1 upgrade, 1 in new slot, 1 block), Size of downloads: 0 kB

!!! 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