unload-feature

[Luc Teirlinck]

There appears to be a problem with packages redefining, say macros,
when those packages subsequently get unloaded using unload-feature.
The original definition does not get restored and trouble ensues.  In
the ielm run below, cl redefines `dolist', we unload cl, the cl
definition of `dolist' remains in place, but `cl-block-wrapper' got
undefined in unloading cl:

ELISP> (setq ll '(1 2))
(1 2)

ELISP> (dolist (x ll x))
nil
ELISP> (load "cl")
t
ELISP> (dolist (x ll x))
nil
ELISP> (unload-feature 'cl)  ;; Long output flushed.
ELISP> (dolist (x ll x))
*** Eval error ***  Symbol's function definition is void: cl-block-wrapper
ELISP>