FFI updates: adding ffi-include, length in values, bugfix cast in calloc.
FFI updates: adding ffi-include, length in values, bugfix cast in calloc.

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