bug#25088: 25.1; feature-unload and reload of cl-defstruct fails

[npostavs]

Eli Zaretskii <eliz@gnu.org> writes:
>
> How risky is this change?  cl-defstruct is a very widely used macro,
> whereas unload-feature is a relatively obscure feature.  Is it really
> worth fixing the (IMO minor) error and risking to break Emacs 25.2?
>
> I don't have an intuition I can trust in these matters, so I need you
> and others who do to offer their opinions, after carefully considering
> the pros and cons.

I think it's safe, but I've been wrong before.  I agree that
unload-feature is sufficiently obscure that this can go to master
instead of emacs-25.

Perhaps the real bug is that unload-feature doesn't undo `put', thus the
compiler-macro still hangs around.