Unused variables removed (many files).

sql/item_func.cc:
  Unused variable 'thd' removed.
sql/item_subselect.cc:
  Unused variable 'type' removed.
sql/slave.cc:
  Unused variable 'return_val' removed.
sql/sql_derived.cc:
  Unused variable 'is_subsel' removed.
sql/sql_parse.cc:
  Unused variables 'pstr' and 'create_info' removed.
sql/sql_prepare.cc:
  Unused variable 'res' removed.
sql/time.cc:
  Unused variable 'str_begin' removed.

sql/item_func.cc

@@ -3196,7 +3196,6 @@ longlong Item_func_is_free_lock::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   String *res=args[0]->val_str(&value);
-  THD *thd=current_thd;
   User_level_lock *ull;
 
   null_value=0;
@@ -3219,7 +3218,6 @@ longlong Item_func_is_used_lock::val_int()
 {
   DBUG_ASSERT(fixed == 1);
   String *res=args[0]->val_str(&value);
-  THD *thd=current_thd;
   User_level_lock *ull;
 
   null_value=1;

sql/item_subselect.cc

@@ -657,7 +657,6 @@ Item_in_subselect::single_value_transformer(JOIN *join,
 	!(select_lex->next_select()))
     {
       Item *item;
-      subs_type type= substype();
       if (func->l_op())
       {
 	/*

sql/slave.cc

@@ -3562,7 +3562,6 @@ err:
 
 static int process_io_rotate(MASTER_INFO *mi, Rotate_log_event *rev)
 {
-  int return_val= 1;
   DBUG_ENTER("process_io_rotate");
   safe_mutex_assert_owner(&mi->data_lock);
 

sql/sql_derived.cc

@@ -117,7 +117,6 @@ static int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
   select_union *derived_result;
   bool is_union= first_select->next_select() && 
     first_select->next_select()->linkage == UNION_TYPE;
-  bool is_subsel= first_select->first_inner_unit() ? 1: 0;
   SELECT_LEX *save_current_select= lex->current_select;
   DBUG_ENTER("mysql_derived");
 

sql/sql_parse.cc

@@ -2004,7 +2004,6 @@ mysql_execute_command(THD *thd)
     {
       /* This is PREPARE stmt FROM @var. */
       String str;
-      String *pstr;
       CHARSET_INFO *to_cs= thd->variables.collation_connection;
       bool need_conversion;
       user_var_entry *entry;
@@ -2614,7 +2613,6 @@ unsent_create_error:
 
   case SQLCOM_OPTIMIZE:
   {
-    HA_CREATE_INFO create_info;
     if (check_db_used(thd,tables) ||
 	check_table_access(thd,SELECT_ACL | INSERT_ACL, tables,0))
       goto error; /* purecov: inspected */

sql/sql_prepare.cc

@@ -849,7 +849,6 @@ static bool insert_params_from_vars_with_log(Prepared_statement *stmt,
 
   List_iterator<LEX_STRING> var_it(varnames);
   String str;
-  const String *res;
   uint32 length= 0;
   if (query->copy(stmt->query, stmt->query_length, default_charset_info))
     DBUG_RETURN(1);

sql/time.cc

@@ -411,7 +411,6 @@ str_to_TIME(const char *str, uint length, TIME *l_time, uint flags,
   ulong not_zero_date, allow_space;
   bool is_internal_format;
   const char *pos, *last_field_pos;
-  const char *str_begin= str;
   const char *end=str+length;
   const uchar *format_position;
   bool found_delimitier= 0, found_space= 0;
@@ -775,7 +774,6 @@ bool str_to_time(const char *str, uint length, TIME *l_time, int *was_cut)
 {
   long date[5],value;
   const char *end=str+length, *end_of_days;
-  const char *str_begin= str;
   bool found_days,found_hours;
   uint state;