#1 sha256: Build problems under Windows

[Holger Dürer]

Package does not build out of the box for me under
Windows with VC++6
Basically, __WIN32__ does not seem to be defined by
default.

I fixed it by adding the following at the top of sha2.h:
#if defined(_MSC_VER)
#define __WIN32__
#endif

[Jeff Connelly]

Logged In: YES
user_id=31953

I encountered the same problem. I think this fix would be
better, because it should work on non-MS Windows compilers:

#ifdef _WIN32
#define __WIN32__
#endif