Compiling it under Windows with MetroWerks v4.x works fine except for a
couple of things. These are the changes I needed to make to config.h:
 
1) MetroWerks defines _MSC_VER as well
129c129
< #ifdef _MSC_VER
---
> #if defined(_MSC_VER) && !defined(__MWERKS__)
138c138
< #ifdef _MSC_VER
---
> #if defined(_MSC_VER) && !defined(__MWERKS__)

2) MetroWerks does not define the rotations:
144a145,163
> #endif
>
> // metrowerks does not define _lrotl and _lrotr
> #if defined(_MSC_VER) && defined(__MWERKS__)
> inline
> word32 _lrotl(const word32 x, const int shift)
> {
>       const word32    cte = sizeof(x) - shift;
>       const word32    ret = (x << shift)|(x >> cte);
>       return ret;
> }
>
> inline
> word32 _lrotr(const word32 x, const int shift)
> {
>       const word32    cte = sizeof(x) - shift;
>       const word32    ret = (x >> shift)|(x << cte);
>       return ret;
> }
 
I'm not yet sure if all runs fine. I'll let you know if I come across any
problems.