When the usersync feature is enabled (which it is by default),
emerge-webrsync uses the owner and group of /usr/portage
(${repo_location}) for the unpacked tree. This commit avoids having
the whole tree be owned by root:root.
RUN echo 'GENTOO_MIRRORS="http://mirror.mcs.anl.gov/pub/gentoo/"' >> /etc/portage/make.conf
#RUN echo 'SYNC="rsync://rsync.us.gentoo.org"' >> /etc/portage/make.conf
RUN mkdir -p /usr/portage
+RUN chown -R portage:portage /usr/portage
RUN emerge-webrsync
RUN emerge --sync --quiet
RUN eselect news read new