Cleanup.
Split 'common/' into commit '2413deb4d5eb41c295bccb70d2c1a2705f7c20aa'

git-subtree-dir: common
git-subtree-mainline: 4bddf6ff1252dda996d9e230fd59c8ec03336ae5
git-subtree-split: 2413deb4d5eb41c295bccb70d2c1a2705f7c20aa