The (new) CxxTest unit tests finally work on Linux. It took a "little" longer than I had hoped (I had to reinstall Ubuntu about 7 times before I figured out that Qemu couldn't deal properly with its own qcow2 image format), but it now works.

However, if anyone familiar with Makefiles wants to check that I didn't make some stupid mistakes, that would be great. (I obviously checked that it still builds and such, but perhaps there are some less obvious problems lurking in the dark.)