Remove SCM_CONT_DYNWIND_MARKER

It is introduced in commit 4fb47f9
The plan was to keep dynamic handler object in the stack frame rather
than a separate handler chain.  The marker is needed to distinguish what
is stored in the stack frame.  However, the idea didn't seem to work well,
and only the unused marker remained.

src/gauche/vm.h

@@ -158,7 +158,7 @@ SCM_EXTERN ScmObj Scm_ContinuationMarkSetToList(const ScmContinuationMarkSet *,
  *
  *   |  base   |
  *   |   pc    |  <-- PCont procedure
- *   |  cpc    |  <-- CCont procedure, NULL, or #<dynamic-handler>
+ *   |  cpc    |  <-- CCont procedure or NULL
  *   | marker  |
  *   | size=N  |
  *   |  denv   |

src/vm.c

@@ -89,8 +89,7 @@ struct ScmContinuationPromptRec {
 /* bitflags for ScmContFrame->marker */
 enum {
       SCM_CONT_SHIFT_MARKER = (1L<<0),
-      SCM_CONT_RESET_MARKER = (1L<<1),
-      SCM_CONT_DYNWIND_MARKER = (1L<<2),
+      SCM_CONT_RESET_MARKER = (1L<<1)
 };
 
 static void push_prompt_cont(ScmVM*, ScmObj, ScmObj);
@@ -102,10 +101,6 @@ static void push_boundary_cont(ScmVM*, ScmObj, ScmObj);
 /* return true if cont has the end marker of partial continuation */
 #define MARKER_FRAME_P(cont)   ((cont)->marker & SCM_CONT_SHIFT_MARKER)
 
-/* return true if cont is of dynamic-wind body */
-#define DYNWIND_FRAME_P(cont)  ((cont)->marker & SCM_CONT_DYNWIND_MARKER)
-
-
 /* A stub VM code to make VM return immediately */
 static ScmWord return_code[] = { SCM_VM_INSN(SCM_VM_RET) };
 #define PC_TO_RETURN  return_code
@@ -1932,9 +1927,7 @@ ScmObj *Scm_pc_PushCC(ScmVM *vm, ScmPContinuationProc *after, int datasize)
 static ScmObj *push_dynamic_handler_cc(ScmVM *vm, ScmPContinuationProc *after,
                                        ScmObj dh, int datasize)
 {
-    ScmObj *data = new_ccont(vm, after, (ScmWord*)dh, datasize);
-    CONT->marker |= SCM_CONT_DYNWIND_MARKER;
-    return data;
+    return new_ccont(vm, after, (ScmWord*)dh, datasize);
 }
 
 /*