Bug#34517 SHOW GLOBAL STATUS does not work properly in embedded server.

      GLOBAL STATUS is calculated by studying the list of threads. In the
        embedded server threads were not linked to the internal list, so the
        calculation always returns 0. Fixed by 'linking' the embedded-server
        threads to the same list

per-file comments:
  libmysqld/lib_sql.cc
Bug#34517 SHOW GLOBAL STATUS does not work properly in embedded server.
    Add newly created 'threads' to the internal thread list.
    Remove them from the list as they're freed.

  mysql-test/r/information_schema.result
Bug#34517 SHOW GLOBAL STATUS does not work properly in embedded server.
    test result

  mysql-test/t/information_schema.test
Bug#34517 SHOW GLOBAL STATUS does not work properly in embedded server.
    test case added

libmysqld/lib_sql.cc

@@ -384,6 +384,7 @@ static void emb_free_embedded_thd(MYSQL *mysql)
   thd->clear_data_list();
   thread_count--;
   thd->store_globals();
+  thd->unlink();
   delete thd;
   mysql->thd=0;
 }
@@ -627,6 +628,7 @@ void *create_embedded_thd(int client_flag)
   bzero((char*) &thd->net, sizeof(thd->net));
 
   thread_count++;
+  threads.append(thd);
   return thd;
 err:
   delete(thd);

mysql-test/r/information_schema.result

@@ -1698,4 +1698,13 @@ drop table if exists t1;drop table if exists
 Warnings:
 Warning	1265	Data truncated for column 'VARIABLE_VALUE' at row 1
 set global init_connect="";
+create table t0 select * from information_schema.global_status where VARIABLE_NAME='COM_SELECT';
+SELECT 1;
+1
+1
+select a.VARIABLE_VALUE - b.VARIABLE_VALUE from t0 b, information_schema.global_status a
+where a.VARIABLE_NAME = b.VARIABLE_NAME;
+a.VARIABLE_VALUE - b.VARIABLE_VALUE
+2
+drop table t0;
 End of 5.1 tests.

mysql-test/t/information_schema.test

@@ -1373,4 +1373,14 @@ drop table if exists t1;drop table if exists t1;";
 select * from information_schema.global_variables where variable_name='init_connect';
 set global init_connect="";
 
+#
+# Bug #34517 SHOW GLOBAL STATUS does not work properly in embedded server.
+#
+
+create table t0 select * from information_schema.global_status where VARIABLE_NAME='COM_SELECT';
+SELECT 1;
+select a.VARIABLE_VALUE - b.VARIABLE_VALUE from t0 b, information_schema.global_status a
+   where a.VARIABLE_NAME = b.VARIABLE_NAME; 
+drop table t0;
+
 --echo End of 5.1 tests.