ffi library port to Windows (WIN32)

hi Etienne,

I started to port the ffi library to Windows (WIN32).

I also discovered that the X86_WIN32 macro that appears in the code 
refers to the following ffi library ports:

 - Cygwin x86
 - Mingw x86

In short, a WIN32 port does exist but both, the C and assembly code, can 
only be compiled with GCC.

As discussed a month ago, I'll be using the #ifdef WIN32 pre-processor 
directive, and will place the project files outside the sablevm tree.


Enrico