I downloaded the DIR-685 GPL and see the readme does not mention which OS to build on. However I do see it mentions downgrading make to v3.80 if you get syntax errors, which implies Fedora 4 perhaps? Furthermore, the readme for the linux kernel mentions using gcc 2.95.3 which also would indicate an ancient distro of Fedora. So I'd try find a really old distro - certainly not 18 - unless you're prepared to try fix the source code to work with a newer version of make, gcc, and all the other libraries. I don't have access to my computer running Fedora 10 at this moment (my daughter is hogging it) but I could try the build when I have a chance and see if it works.