patch from okuoku fixing ffi tests on cygwin
patch from okuoku fixing ffi tests on cygwin

holmescn/chibi-scheme,holmescn/chibi-scheme,holmescn/chibi-scheme,holmescn/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme,holmescn/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme,norton/chibi-scheme