bug#5293: 23.1; unload-feature on buffer-local hooks

[Kevin Ryde]

reopen 5293
thanks

Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>> No, just the hooks.  If it makes sense to remove unloaded funcs from
>> hook global values then surely the same rationale applies to remove them
>> from the buffer-local values too.
>
> Agreed.  Someone would have to try it out to see if it can be
> done efficiently.

Reopened for that, or failing that then for clarifying the docstring.

I imagine there's not normally many hooks or many buffers, or many
buffer-local variables, whichever one of those was the efficient way to
scan ... and unload-feature isn't used very much anyway.

(Actually the way unload-feature seems not much used and not getting
much attention from packages makes me wonder if it's worth bothering.
But if unload-feature did a little more then it would increase its
usefulness, perhaps to the point where it would be used more :-)