bug with -O -ffi and multiple module

[Simon Marlow]

> Okay, here's a weird one.  There's something wrong with the 
> ffi when using
> -O and the foreign imports are from another module.  For example, our
> foreign module, foo.c contains functions:
> 
>    void* openFile(char*fn);
>    void closeFile(void*f);
>    float readFloat(void*f);
> 
> which are interfaced from foo.h.  We have a FooIntr.hs interface file,
> which looks like:
> 
>    foreign import ccall "foo.h openFile"  c__openFile  :: Ptr 
> CChar -> IO
>        (Ptr ())
>    foreign import ccall "foo.h closeFile" c__closeFile :: Ptr 
> () -> IO ()
>    foreign import ccall "foo.h readFloat" c__readFloat :: Ptr () -> IO
>        CFloat

I think what you're seeing here is an instance of this bug:

http://sourceforge.net/tracker/index.php?func=detail&aid=655400&group_id
=8032&atid=108032

Workaround: use -#include instead of including the header file in the
FFI spec.

Cheers,
	Simon