Currently, the only way to build zabbix_get and zabbix_sender is to configure with --enable-agent.

Drawbacks:

(1) compilation takes noticeably longer on slower machines;
(2) it is not exactly intuitive that we should specify --enable-agent to compile zabbix_get and zabbix_sender;
(3) on platforms where agent is not yet supported, we might still want zabbix_sender, and if agent compilation fails then we also do not get zabbix_sender (without additional effort).