File ffcall/README.win32 from the latest check-in

Installation on Win32 (WinNT, Win95):

- Requires MS Visual C/C++ 4.0 or 5.0.

- Cannot build in a separate directory.

- Build instructions:

   Make sure that the MSVC4.0 or MSVC5.0 utilities ("cl" etc.) are found in
   PATH.

        nmake -f Makefile.msvc

- Installation:

   Copy avcall/avcall.lib, vacall/vacall.lib, trampoline/trampoline.lib,
   callback/callback.lib to your library repository.