programs have their own tc7 now

* libguile/tags.h (scm_tc7_program):
* libguile/programs.h: Programs now have their own tc7 code. Fix up the
  macros appropriately.

* libguile/programs.c: Remove smobby bits, leaving marking, printing,
  and application for other parts of Guile.

* libguile/debug.c (scm_procedure_source):
* libguile/eval.c (scm_trampoline_0, scm_trampoline_1)
  (scm_trampoline_2): Add cases for tc7_program.
* libguile/eval.i.c (CEVAL, SCM_APPLY):
* libguile/evalext.c (scm_self_evaluating_p):
* libguile/gc-card.c (scm_i_sweep_card, scm_i_tag_name):
* libguile/gc-mark.c (1):
* libguile/print.c (iprin1):
* libguile/procs.c (scm_procedure_p, scm_thunk_p)
* libguile/vm-i-system.c (make-closure): Adapt to new procedure
  representation.

* libguile/procprop.c (scm_i_procedure_arity): Do the right thing for
  programs.
* test-suite/tests/procprop.test ("procedure-arity"): Arity test now
  succeeds.

* libguile/goops.c (scm_class_of): Programs now belong to the class
  <procedure>, not a smob class.

* libguile/vm.h (struct vm, struct vm_cont):
* libguile/vm-engine.c (vm_engine):
* libguile/frames.h (SCM_FRAME_BYTE_CAST, struct vm_frame):
* libguile/frames.c (scm_c_make_vm_frame): Fix usages of scm_byte_t,
  changing them to scm_t_uint8.

libguile/gc-card.c

@@ -162,6 +162,8 @@ scm_i_sweep_card (scm_t_cell *card, SCM *free_list, scm_t_heap_segment *seg)
 	  break;
 	case scm_tc7_variable:
 	  break;
+	case scm_tc7_program:
+	  break;
 	case scm_tcs_subrs:
 	  /* the various "subrs" (primitives) are never freed */
 	  continue;
@@ -386,6 +388,8 @@ scm_i_tag_name (scm_t_bits tag)
       return "closures";
     case scm_tc7_pws:
       return "pws";
+    case scm_tc7_program:
+      return "program";
     case scm_tc7_wvect:
       return "weak vector";
     case scm_tc7_vector: