Re: Changing of line format and undo

[Richard Stallman]

    BTW, this change does not fix the original problem of recording undo
    information for changing line endings; it only addresses undo for
    multibyte.

set-buffer-multibyte changes the buffer contents, so it ought to be
undoable.  Changing buffer-file-coding-system does not change the buffer
contents, so I am not sure it ought to be undoable.  It only affects
how the buffer will be saved.  set-visited-file-name also affects
how the buffer will be saved, and we did not make it undoable.

I am not convinced it is correct to try to make undo cover changes
in how the buffer would be saved.