A revised patch for dlclose

[Jim Blandy]

> That is fine with me as long as it is fixed in 5.0. There is no excuse
> not to get gdb to work with dlclose. "I don't like the way it fixes the
> bug" doesn't count unless you can provide a different approach. I
> think it is unreasonable to have a perfect fix for every bug. We can
> work a better one after 5.0 if we don't have the time now.

I believe there is such a thing as a correct fix.  And I don't think
they so hard to find that one must always shamble towards correctness.
I think it's fine to reject a patch that one knows has bugs as serious
as the extant code.