Better -x handling.  If the language defines the standard port
parameters but doesn't bind them, we bind them to stdin/stdout/stderr.
If the parameters are not defined at all, we abort.
Making sexp_make_primitive_env available from Scheme.
Adding the (chibi primitive) module to access this directly.
Removing the deprecated (scheme) module.
Making new -x handling work with -e/-p.
Optimizing the -xchibi.primitive case to use -q (i.e. no file I/O).
Adding -? to print help with no "unknown option" error message.
Patch from Peter Michaux to allow reordering the heap struct
so the data pointer is not the last element.
Patch from Per Bothner to verify new boolean literals with delimiters.
Exporting conf-source
Reverting patch from Peter Michaux.
Adding string and symbol quote delimiters to list of read delimiters in (scheme read).