www.zabbix.com/download.php

First, install xcode. I know, groans abound, but it's required so just do it unless you feel like you want to trust my binaries. Secondly, grab the zabbix source code, it's free and relatively small.

Next, follow the sequence of steps exactly, it is easy, fast and relatively pain-free. From a shell as an administrative user:

Install command-line tools:

userownloads user$ xcode-select --install

Untar/uncompress the latest tarball (2.4.5)

userownloads user$ tar -zxvpf zabbix-2.4.5.tar.gz

Switch to the tarball directory

user:~ user$ cd zabbix-2.4.5

Run the configure sсript with the --enable-agent switch

user:zabbix-2.4.5 user$ ./configure --enable-agent

Make the executable

user:zabbix-2.4.5 user$ make

Make the necessary local directories

user:zabbix-2.4.5 user$ sudo mkdir -p /usr/local/etc /usr/local/sbin

Copy the configuration file to the local etc directory

user:zabbix-2.4.5 user$ sudo cp ./conf/zabbix_agentd.conf /usr/local/etc/

Copy the daemon file to the local sbin directory

user:zabbix-2.4.5 user$ sudo cp ./src/zabbix_agentd /usr/local/sbin

Edit the agent daemon file (beyond the scope of this document)

user:zabbix-2.4.5 user$ vi /usr/local/etc/zabbix_agentd.conf

Start the agent, and enjoy!

user:zabbix-2.4.5 user$ /usr/local/sbin/zabbix_agentd