fixed SQL_SELECT option with UNIONs

mysql-test/r/query_cache.result:
  test of SQL_CACHE with UNIONs
mysql-test/t/query_cache.test:
  test of SQL_CACHE with UNIONs

mysql-test/r/query_cache.result

@@ -237,13 +237,18 @@ a
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
-select sql_cache * from t1;
+select sql_cache * from t1 union select * from t1;
 a
 1
 2
 3
 set query_cache_type=2;
-select sql_cache * from t1;
+select sql_cache * from t1 union select * from t1;
+a
+1
+2
+3
+select * from t1 union select sql_cache * from t1;
 a
 1
 2
@@ -253,7 +258,7 @@ Variable_name	Value
 Qcache_hits	4
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
-Qcache_queries_in_cache	1
+Qcache_queries_in_cache	2
 set query_cache_type=on;
 reset query cache;
 show status like "Qcache_queries_in_cache";

mysql-test/t/query_cache.test

@@ -144,9 +144,10 @@ create table t1 (a int not null);
 insert into t1 values (1),(2),(3);
 select * from t1;
 show status like "Qcache_queries_in_cache";
-select sql_cache * from t1;
+select sql_cache * from t1 union select * from t1;
 set query_cache_type=2;
-select sql_cache * from t1;
+select sql_cache * from t1 union select * from t1;
+select * from t1 union select sql_cache * from t1;
 show status like "Qcache_hits";
 show status like "Qcache_queries_in_cache";
 set query_cache_type=on;

sql/sql_cache.cc

@@ -2439,7 +2439,7 @@ TABLE_COUNTER_TYPE Query_cache::is_cacheable(THD *thd, uint32 query_len,
 
   if (lex->sql_command == SQLCOM_SELECT &&
       (thd->variables.query_cache_type == 1 ||
-       (thd->variables.query_cache_type == 2 && (lex->select->options &
+       (thd->variables.query_cache_type == 2 && (lex->select_lex.options &
 						 OPTION_TO_QUERY_CACHE))) &&
       thd->safe_to_cache_query)
   {

sql/sql_yacc.yy

@@ -1530,7 +1530,10 @@ select_option:
 	    Select->options|= OPTION_FOUND_ROWS;
 	  }
 	| SQL_NO_CACHE_SYM { current_thd->safe_to_cache_query=0; }
-	| SQL_CACHE_SYM    { Select->options|= OPTION_TO_QUERY_CACHE; }
+	| SQL_CACHE_SYM
+	  {
+	    Lex->select_lex.options|= OPTION_TO_QUERY_CACHE;
+	  }
 	| ALL		{}
 	;