Commit Briefs
fossil: move from liboventi to libthread and libventi
R=rsc https://codereview.appspot.com/13504049
fossil: import from plan 9
R=rsc https://codereview.appspot.com/7988047
R=rsc https://codereview.appspot.com/13504049
R=rsc https://codereview.appspot.com/7988047