Proxy needs zabbix_proxy.conf twice (in /etc/zabbix & in /usr/local/etc)

Zabbix Proxy needs the configuration file zabbix_proxy.conf in two directories (/etc/zabbix and /usr/local/etc), otherwise it would not start!

Error-Messages:
zabbix_proxyconfiguration file /etc/zabbix/zabbix_proxy.conf does not exist.
&
zabbix_proxyconfiguration file /usr/local/etc/zabbix_proxy.conf does not exist.

Even with explicit using compilation variable "--sysconfdir=/etc/zabbix" it wouldnt work...