Adding sexp_current_input_port(ctx) and sexp_current_output_port(ctx) macros.
Adding sexp_current_input_port(ctx) and sexp_current_output_port(ctx) macros.

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