broken memory management in TokuDB 5.6.28-76.1

5.6:
https://github.com/georgelorchpercona/percona-server/tree/ps-5.6-DB-962
http://jenkins.percona.com/job/percona-server-5.6-param/1127/
https://github.com/percona/percona-server/pull/480

5.7:
https://github.com/georgelorchpercona/percona-server/tree/ps-5.7-DB-962
http://jenkins.percona.com/view/5.7/job/mysql-5.7-param/152/
https://github.com/percona/percona-server/pull/481

MariaDB is apparently unable to merge TokuDB changes for the last 7 months due to this bug (last merge was for 5.6.26-74.0)