These are the available versions for Thor.
	default      - with lots of assertion checks
	optimized    - optimized version

You may wish to use the following version for building a theta compiler.
	compiler     - links compiler code into the front-end

The following versions are intended only for use in Thor development.
Use at your own risk.
	debug        - inquire + OO7 + tests-th
	oo7_th       - oo7 implemented in Theta
	inquir-th    - inquir implemented in Theta
	tests-th     - tests with code implemented in Theta
	labbase      - the genome project database
	minimal      - no auxiliary types
	watch        - turn on tons and tons of tracing code
	compiler_test - build compiler and dtheta
