-`utils.sh` only needs to know the path to the `tests` directory within
-the source and the build directories. By default, `utils.sh` assumes the
-build is in tree, that is, you ran `./configure` from the source's root
-directory, and sets the `BT_TESTS_SRCDIR` and `BT_TESTS_BUILDDIR`
-environment variables accordingly. You can override those variables, for
-example if you build out of tree.