How to follow the end of *Messages* buffer in Emacs?

[Yves Baumes]

I am playing with Elisp, and I find convenient to have the *Messages*
buffer always open in a window in my frame.

I discovered recently that sometimes the buffer stops following the last
lines. If I want to see the last appended lines in this buffer, I need
to go in the buffer and jump to the end manually, with M->. Which is
quite annoying and disruptive.

I am trying to reproduce the "tail -f" command line, in a buffer. Of
course 'auto-revert-tail-mode complains that the *Messages* is not a
visited file... As a consequence, this mode does not want to work. But
it gave me the idea to add a function hook when the buffer is modified.
That function would jump to (point-max) each time that buffer is
modified.

Here is my own attempt, invoked from *Messages* buffer, with M-:
(add-hook
 'after-change-functions
 (lambda (s e l) (goto-char (point-max)))
 nil t)

But it does not work. The (point) remains in the same place while I see
the buffer is growing... The lambda function does not produce any error,
otherwise it would have been removed from the 'after-change-functions
hook and C-h k 'after-change-functions shows it is present.

Any better suggestions?