[jhc] Threading and atoms.

[Lemmih]

Hiya,

When I use -threaded and -N2 in jhc, atoms fail in spectacular ways.
So far I've seen:
>>> internal error:
fullCheck': Instance at .iJhc.Monad.return.Jhc.Prim.IO x6598
Strong': ? x6598
Cannot strong:
(?, [x6598])

and:
stringlib: error alocating memory


Are atoms in some way not thread-safe enough?

-- 
Cheers,
 Lemmih