A revised patch for dlclose

[Jim Blandy]

> I do agree with HJ about one thing, though, which is that this issue
> is rather important.  I'm trying to put my money where my mouth is by
> writing code but I'll have to admit that JimB's message left me a
> little unsure about where to turn.

You mean the vague "I don't understand the logic" comment?  I concede
that it's not especially constructive criticism.  But it was the
truth.  :)

I think I've got some idea of how to fix this, but you know how these
things go --- don't let that stop you from thinking about it yourself.