Zabbix

.......PS. [ZBXNEXT-7109] fixed build on BSD like and other systems without sigqueu support

Merge in ZBX/zabbix from feature/ZBXNEXT-7109-5.5 to master

* commit '31392095d3cf3cbcd1217ba8996388c5f801447e':
  .......PS. [ZBXNEXT-7109] fixed unused variable warning
  .......PS. [ZBXNEXT-7109] fixed build on systems without sigqueue