Zabbix

.......PS. [ZBXNEXT-8166] fixed build on systems with older libevent versions

Merge in ZBX/zabbix from feature/ZBXNEXT-8166-6.3 to master

* commit '460859da155972b2c6af2e0b032321d13585d571':
  .......PS. [ZBXNEXT-8166] replaced evuser convenicence defines