executable in order to avoid a collision with the BSD games port of
the ancestral 1977 version.
+The distribution has three build-time depedencies: Python 3, Python 3
+YAML, and the linenoise library. It builds a pure C executable.
+
You can run a regression test on the code with 'make check'. Extreme
care has been taken to not silently change gameplay. By policy, all
user-visible changes from 2.5 are revertible with the -o (oldstyle)