Any chance you have gcc installed on your Pi? If so, what is the output of the command: gcc -dumpmachine
I might be able to use a pre-built cross compiler available already for Ubuntu but I'm not sure yet. It sounds like depending upon which Pi distro is used, it may want arm-unknown-linux-gnueabi or it may want arm-unknown-linux-gnueabihf where the "hf" stands for hardware floating point (vs. softfp or none).