I actually got the open source FPGA tools working on the RPi a few days ago, but I've been remiss in posting to this log.

Ed Vidal provided me with an archive that I could load onto my RPi using the squashfs tools. Unfortunately, they didn't work. It turned out I was running the Raspbian Wheezy distribution and I had to upgrade to Jessie. After doing that, it was easy to compile a simple blinker example. (Ed even prepared the example with the correct pin assignments for the CAT Board. What a guy!) Then it was just a matter of downloading the bitstream to the CAT Board and watching the LEDs turn on and off. Check out the video below for all the excitement!

With the RPi-host FPGA tools in place, example designs can now be compiled to test the SDRAM and I/O ports.