GHC 5.05 panic in speceval_2 branch

[Robert Ennals]

> I've no idea what state the speceval_2 branch is in. It's where Robert
> was working on optimistic evaluation.  I'll let him comment.

[snip]

> | ghc-5.05: panic! (the `impossible' happened, GHC version 5.05):
> |          Optimistic Evaluation does not currently support native code
> | generation
> |      Use -fvia-C or -O

I think the panic message basically says all there is to say.

I never got round to updating the native code generator to support optimistic 
evaluation. If you want to compile with optimistic evaluation enabled (which 
is the default in the speceval_2 branch) then you have to compile via C, 
rather than via the native code generator. This can be done by using either 
-fvia-C or -O when compiling programs.

The alternative would have been for me to automatically set -fvia-C if 
optimistic evaluation is enabled, but I thought that people might find that 
confusing.


-Rob