Ever had a massive emerge package list and one package refuses to compile?  This happened to me when running an "emerge -e system". You can run an "emerge -1 <package>" upgrade/downgrade, but this won't remove it from the emerge queue.  Running "emerge --resume" will continue the queue starting with the package that failed.

Fear not, "vi /var/cache/edb/mtimedb".  Look for the package that you have just successfully emerged and remove that section from the list.

"mergelist": [
                        [
                                "ebuild",
                                "/",
                                "www-client/chromium-29.0.1547.32",
                                "merge"
                        ],

Running "emerge --resume" will now continue without trying to remerge the problematic package.