I have the same issue, with last version of GCC (new install+updated all gentoo packages).
I get same errors as you do, with
#emerge planeshift.
I looked on google for anything looking like the errors i get and found nothing. Arrrhg
Prolly need to try with the .tar.gz
EDIT : and of course, like you all dependencies = no problem. Did the etc-update too etc.. works fine, appart emerge planeshift that spams me with something saying csCLList.h is deprecated or something. Then i get same errors than you at end.