Tooling support for FreeBSD.

This is still really sketchy, as I'm still on 9.x which doesn't have
support in BASE for a lot of the toolchain functionality needed.

Problems:

 * You have to install premake4.4-beta5. I have a local port for it ;_;
 * You have to instal lang/gcc47. I needed something newer than 4.2.1,
   and that's what I already had installed.
 * i386 is completely broken for unknown reasons (makefile is
   configured for amd64 only).