Cross compiling

You're better off setting up a FreeBSD virtual machine, in VirtualBox or something, and compiling directly on FreeBSD.

 

For the most part, configuring, building, and installing open-source software is almost exactly the same.

That being said, you most likely will run into dependancies, and that can cause headaches.

The best way to install open-source software is to use a package manager, like MacPorts. There's also Homebrew, which I haven't tried, and Fink, which I don't know if it supports 64-bit builds in most of their packages.

 

What, specifically, did you need from FreeBSD? OS X does have some BSD code in it.

 

It sounds like you want to do the compile on your Mac, and then have a binary come out that will run on FreeBSD. Right?

That IS possible. Last time I did it (Linux compiling for AIX) it took building GCC from source and then the various libraries. It was not a small effort. Today, I would agree with the suggestion earlier to install FreeBSD on a vm and compile there. Much more straightforward and fewer headaches.

 

Cross compiling from OS X is popular with Raspberry Pi hackers (though typically cross compiling Linux/Linux executables). You might want to check their forum.