Fix bug in _get method of deque container.

m-deque.h

@@ -680,12 +680,11 @@
     assert (key < d->count);						\
     const size_t index0 = d->front->index;				\
     size_t count = 0;							\
-    M_C(name, _node_list_it_t) it;					\
     /* This loop is in log(N) since the size increase exponentially.*/	\
-    for(M_C(name, _node_list_it)(it, d->list) ;				\
-	!M_C(name, _node_list_end_p)(it) ;				\
-	M_C(name, _node_list_next)(it) ){				\
-      M_C(name, _node_t) *n = M_C(name, _node_list_ref)(it);            \
+    for(M_C(name, _node_t) *n = d->front->node;                         \
+	n != NULL ;                                                     \
+	n = (n == d->back->node) ? NULL :                               \
+          M_C(name, _node_list_next_obj)(d->list, n) ){                 \
       if (index0 + key < count + n->size) {				\
 	return &n->data[index0 + key - count];				\
       }									\