Since v1.4.9, another stat command has been added to playTests.sh.
Similar to other uses in this file, it attempts to use BSD syntax on
Darwin/BSD, and must be patched to unconditionally use GNU syntax.
The previous CMake version did not run any tests, the current version
tries to run all tests (I could not await their completion), and the
last GNU Make version ran `make -C tests shortest` which ran only
playTests.sh, so I've enabled only the playTests test.