Please help me compiling sockperf for FreeBSD

I would love to have sockperf for FreeBSD for benchmarking my network.

It can be found here
Works great for Linux, but when I try to compile it for FreeBSD I get the following error

In file included from src/Client.cpp:29:0:
src/Defs.h:460:10: error: 'hash' is not a class template

Is this some kind of a c++ standard issue, is it a missing CFLAG?
It looks like hash is not even supposed to be defined when compiling on FreeBSD. Can you check to make sure the value __FreeBSD__ is defined somewhere?