Fix unit test with gnustep 1.24

The unit test TestVersit fails with GNUstep 1.24 because the way the elements are ordered changed (see also http://bugs.debian.org/749554). Given that the ordering is stable, but just changed in 1.24, I fixed it by checking for both.

I also added $(TEST_TOOL) as dependency of make check so that running make check will result in recompiling the unit tests if those have been changed.