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

[npostavs]

Eli Zaretskii <eliz@gnu.org> writes:
>> Perhaps the real bug is that unload-feature doesn't undo `put', thus the
>> compiler-macro still hangs around.
>
> If this means there could be another, safer way of fixing this, please
> show the details.

Not sure how much safer this is, I think we would have to record the
which symbol plists are being modified during `load' so that
`unload-feature' could find them in `load-history' and reverse them
along with functions definitions.  This would get rid of the
compiler-macro entries that were added to cl-defstruct accessor function
symbols, and so they would load successfully the second time round just
like the first (presumably).