This program requires the SBCL Common Lisp system (http://www.sbcl.org)
to compile and run. Because of its use of a new feature in the 
sb-executable module, vcs-tree requires SBCL version 0.8.3.55 or greater.

Once you have SBCL installed on your system, you can give the command
   make
which will create the executable file "vcs-tree". You can then copy
that file to any directory in your path, such as /usr/local/bin/