[haskell-llvm] enforce block structure of functions

[Henning Thielemann]

On Sun, 10 Oct 2010, Henning Thielemann wrote:

>  Since we recently started to use the monadic result () for instructions
> without a result like 'store', we can no longer use the type synonym
> Terminate = (). But we could add a new type (data Terminate = Terminate)

I see, that there is such a definition in a comment in Core.CodeGen.

> or just (data Terminate).