How to copy hash table?

[Roland Orre]

In earlier guiles, where hash-tables were vectors, I used copy-tree to
copy a hash table. Now in guile-1.7 copy-tree of the hash-table gives me
the same hash table back, which I assume is correct for atomic objects.

What I want is a table where the handles are copies so when modifying the
values in the new table it won't affect the original.

I guess there exists no trick to generally copy objects.

(Of course, for now, to overcome this I'm using hash-for-each but I'm
 curios about the general issue)

/Roland