24.0.90; Behaviour of add-file-local-variable

Transcripts of exchanges on emacs-devel.
http://lists.gnu.org/archive/html/emacs-devel/2011-10/msg00850.html
http://lists.gnu.org/archive/html/emacs-devel/2011-10/msg00867.html

Additional note: All other file-local related commands may have to be
audited for the requested behaviour.