On a stable system logrotate-3.8.0 will not rotate /var/log/portage/elog/summary.log because portage is lacking the line "su portage portage" in file "/etc/logrotate.d/elog-save-summary".
"error: skipping "/var/log/portage/elog/summary.log" because parent directory has insecure permissions (It's world writable or writable by group which is not "root") Set "su" directive in config file to
tell logrotate which user/group should be used for rotation."
I plan to have portage-18.104.22.168 marked stable in a couple of weeks.
*** This bug has been marked as a duplicate of bug 374287 ***