To start an application on port 80 being not root:

sysctl net.inet.ip.portrange.reservedhigh=79

That will allow to bind an application in any port > 79, to allow any port:

sysctl net.inet.ip.portrange.reservedhigh=0

Add this to /etc/sysctl.conf to keep changes persistent across reboots:

net.inet.ip.portrange.reservedhigh=79