kosc@tabitha ~ $ emerge -upDN world

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

Calculating dependencies... done!
[ebuild     U  ] app-arch/xz-utils-5.2.0 [5.0.7]
[ebuild     U  ] dev-db/redis-2.8.19 [2.8.17]
[ebuild   R    ] dev-python/django-1.7  USE="(-postgres%)"
[ebuild     U  ] sys-libs/tdb-1.3.4 [1.3.3]
[ebuild     U  ] sys-apps/man-db-2.7.1 [2.6.7.1]
kosc@tabitha ~ $ cat /etc/portage/package.use/django
dev-python/django postgres