(1) Turbo closure patch

To make the turbo closure stuff work, make the following changes to KCL.
These changes can also work for an IBCL.

The first of these changes enables turbo closures.  The second change
pushes :turbo-closure on the *features* list so that PCL will know that
turbo closures are enabled.

Note that these changes have to be made before PCL is compiled, and a
PCL which is compiled in a KCL/IBCL with these changes can only be run
in a KCL/IBCL with these changes.

(1-1) edit the function mark_object in the file kcl/c/gbc.c,
changing the lines:
----------
	case t_cclosure:
		mark_object(x->cc.cc_name);
		mark_object(x->cc.cc_env);
		mark_object(x->cc.cc_data);
		if (x->cc.cc_start == NULL)
			break;
		if (what_to_collect == t_contiguous) {
			if (get_mark_bit((int *)(x->cc.cc_start)))
				break;
			mark_contblock(x->cc.cc_start, x->cc.cc_size);
			if (x->cc.cc_turbo != NULL) {
				for (i = 0, y = x->cc.cc_env;
				     type_of(y) == t_cons;
				     i++, y = y->c.c_cdr);
				mark_contblock((char *)(x->cc.cc_turbo),
					       i*sizeof(object));
			}
		}
		break;
----------
to
----------
	case t_cclosure:
		mark_object(x->cc.cc_name);
		mark_object(x->cc.cc_env);
		mark_object(x->cc.cc_data);
		if (what_to_collect == t_contiguous)
		        if (x->cc.cc_turbo != NULL) {
				for (i = 0, y = x->cc.cc_env;
				     type_of(y) == t_cons;
				     i++, y = y->c.c_cdr);
				mark_contblock((char *)(x->cc.cc_turbo),
					       i*sizeof(object));
			}
		if (x->cc.cc_start == NULL)
			break;
		if (what_to_collect == t_contiguous) {
			if (get_mark_bit((int *)(x->cc.cc_start)))
				break;
			mark_contblock(x->cc.cc_start, x->cc.cc_size);
		}
		break;
----------

(1-2) edit the function init_main in the file kcl/c/main.c,
change the lines where setting the value of *features* to add a :turbo-closure
into the list in your KCL/IBCL.

For example, in Sun4(SunOS) version of IBCL
changing the lines:
----------
	make_special("*FEATURES*",
		     make_cons(make_ordinary("SUN4"),
		     make_cons(make_ordinary("SPARC"),
		     make_cons(make_ordinary("IEEE-FLOATING-POINT"),
		     make_cons(make_ordinary("UNIX"),
		     make_cons(make_ordinary("BSD"),
		     make_cons(make_ordinary("COMMON"),
		     make_cons(make_ordinary("IBCL"), Cnil))))))));
----------
to
----------
	make_special("*FEATURES*",
		     make_cons(make_ordinary("SUN4"),
		     make_cons(make_ordinary("SPARC"),
		     make_cons(make_ordinary("IEEE-FLOATING-POINT"),
		     make_cons(make_ordinary("UNIX"),
		     make_cons(make_ordinary("BSD"),
		     make_cons(make_ordinary("COMMON"),
		     make_cons(make_ordinary("IBCL"),
		     make_cons(make_keyword("TURBO-CLOSURE"), Cnil)))))))));
----------
