fix indexing of long instructions

H/headclause.h

@@ -6,6 +6,9 @@
   while (TRUE) {
     op_numbers op = Yap_op_from_opcode(cl->opc);
     switch (op) {
+    case _ensure_space:
+      cl = NEXTOP(cl,Osbpa);
+      break;
     case _native_me:
       cl = NEXTOP(cl,aFlp);
       break;

misc/buildops

@@ -851,7 +851,7 @@ opinfo("p_nonvar_x",[body,ifthenelse]).
 opinfo("p_nonvar_y",[body,ifthenelse]).
 opinfo("save_b_x",[body,new("x")]).
 opinfo("save_b_y",[body,new("y")]).
-opinfo("ensure_space",[body]).
+opinfo("ensure_space",[]).
 opinfo("write_x_loc",[body]).
 opinfo("write_x_var",[body,new("x")]).
 opinfo("write_y_var",[body,new("y")]).