void ARDOUR::IO::meter, 2538 error compiling ardour

I am trying to install ardour from FreeBSD ports. I have tried on a few different systems including a fresh install, but I am getting the following error on all of the machines I attempt to install on.

libs/ardour/io.cc: In Member function 'void ARDOUR::IO::meter
libs/ardour/io.cc:2538: error: no matching function for call to ‘max(float&,double)’

Does anyone have any ideas how I can solve this IO.CC / io meter problem?

Thanks in advance.

This problem existed only with FreeBSD 7.1. It does not exist in 7.2.

I source-updated the system to 7.2 and it’s running fine.