remove debug frames

remove debug frames

* libguile/debug.h (scm_t_debug_frame): Remove this type, as it was
  internal to the old evaluator.
  (SCM_EVALFRAME, SCM_APPLYFRAME, SCM_VOIDFRAME, SCM_MACROEXPF)
  (SCM_TAILREC, SCM_TRACED_FRAME, SCM_ARGS_READY, SCM_DOVERFLOW)
  (SCM_MAX_FRAME_SIZE, SCM_FRAMETYPE)
  (SCM_EVALFRAMEP, SCM_APPLYFRAMEP, SCM_VOIDFRAMEP, SCM_MACROEXPFP)
  (SCM_TAILRECP, SCM_TRACED_FRAME_P, SCM_ARGS_READY_P, SCM_OVERFLOWP)
  (SCM_SET_MACROEXP, SCM_SET_TAILREC, SCM_SET_TRACED_FRAME)
  (SCM_SET_ARGSREADY, SCM_SET_OVERFLOW)
  (SCM_CLEAR_MACROEXP, SCM_CLEAR_TRACED_FRAME, SCM_CLEAR_ARGSREADY):
  Remove macro accessors to scm_t_debug_frame.
  (SCM_DEBUGOBJP, SCM_DEBUGOBJ_FRAME, SCM_SET_DEBUGOBJ_FRAME):
  (scm_debug_object_p, scm_make_debugobj): Remove debugobj accessors.
  (scm_i_unmemoize_expr): Remove unused declaration.

* libguile/debug.c (scm_debug_options): No more max limit on frame
  sizes.
  (scm_start_stack): Just call out to scm_vm_call_with_new_stack.
  (scm_debug_object_p, scm_make_debugobj, scm_init_debug): No more
  debugobj smob type.

* libguile/deprecated.h:
* libguile/deprecated.c (scm_i_deprecated_last_debug_frame)
  (scm_last_debug_frame): Remove deprecated debug-frame bits.

* libguile/stacks.c (scm_make_stack): Rework this function and its
  dependents to only walk VM frames.
  (scm_stack_id): Call out to the holder of the VM frame in question,
  which should be a VM or a VM continuation, for the stack ID. Currently
  this bit is stubbed out.
  (scm_last_stack_frame): Removed. It seems this is mainly useful for a
  debugger, and we need to rewrite the debugger to work on the Scheme
  level.

* test-suite/tests/continuations.test ("continuations"): Remove test for
  last-stack-frame.

* libguile/continuations.h (struct scm_t_contregs):
* libguile/continuations.c (scm_make_continuation):
  (copy_stack_and_call, scm_i_with_continuation_barrier): No need to
  save and restore debug frames.

* libguile/threads.h (scm_i_thread): Don't track debug frames.
  (scm_i_last_debug_frame, scm_i_set_last_debug_frame): Remove macro
  accessors.

* libguile/threads.c (guilify_self_1): Don't track debug frames.

* libguile/throw.c: No need to track debug frames in a jmpbuf.

* libguile/vm-engine.c (vm_engine, VM_PUSH_DEBUG_FRAMES): Don't push
  debug frames.

* libguile/vm.h:
* libguile/vm.c (scm_vm_call_with_new_stack): New function. Currently
  stubbed out though.