Cleanup.

sql/sql_base.cc:
  Cleanup, remove a warning.
sql/sql_select.h:
  Cleanup: remove a warning.

sql/sql_base.cc

@@ -3594,7 +3594,6 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
 {
   Field_iterator_table_ref it_1, it_2;
   Natural_join_column *nj_col_1, *nj_col_2;
-  const char *field_name_1;
   Query_arena *arena, backup;
   bool add_columns= TRUE;
   bool result= TRUE;
@@ -3627,6 +3626,7 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
   {
     bool is_created_1;
     bool found= FALSE;
+    const char *field_name_1;
     if (!(nj_col_1= it_1.get_or_create_column_ref(&is_created_1)))
       goto err;
     field_name_1= nj_col_1->name();
@@ -3823,7 +3823,6 @@ store_natural_using_join_columns(THD *thd, TABLE_LIST *natural_using_join,
 {
   Field_iterator_table_ref it_1, it_2;
   Natural_join_column *nj_col_1, *nj_col_2;
-  bool is_created;
   Query_arena *arena, backup;
   bool result= TRUE;
   List<Natural_join_column> *non_join_columns;

sql/sql_select.h

@@ -174,7 +174,9 @@ typedef struct st_rollup
 
 class JOIN :public Sql_alloc
 {
- public:
+  JOIN(const JOIN &rhs);                        /* not implemented */
+  JOIN& operator=(const JOIN &rhs);             /* not implemented */
+public:
   JOIN_TAB *join_tab,**best_ref;
   JOIN_TAB **map2table;    // mapping between table indexes and JOIN_TABs
   JOIN_TAB *join_tab_save; // saved join_tab for subquery reexecution
@@ -286,12 +288,6 @@ class JOIN :public Sql_alloc
     init(thd_arg, fields_arg, select_options_arg, result_arg);
   }
 
-  JOIN(JOIN &join)
-    :fields_list(join.fields_list)
-  {
-    init(join.thd, join.fields_list, join.select_options,
-         join.result);
-  }
 
   void init(THD *thd_arg, List<Item> &fields_arg, ulonglong select_options_arg,
        select_result *result_arg)