The eclass tests, found under eclass/tests, are currently not run automatically. This yields the danger that the tests rot and decay over time. In fact, I believe this already started to happen.
Ideally the eclass tests are automatically run with the normal QA checks for ::gentoo. A single entry point to run the eclass testsuite is a prerequisite for this. This patch adds, in form of a Makefile, such an entry point. Driving the tests via Make allows us to exploit Make's built-in features, like potentially running the tests in parallel.
