Also fix defsystem.

ERROR-BEHAVIOUR was renamed to ERROR-BEHAVIOR.

Support clozure for mkdir and setenv (need to be moved away).

Be more lenient in list-as-tokens: accept symbols and pathnames as first sub-token.
Accept integers as simple-command-line-token's.
Remove duplicate defmethod print-object.

Add zglob, zglobcmd.
Remove first-and-only, current-directory functions (use xcvb-driver instead).

Don't use the limited SBCL backend by default, for now. Requires more work.

plus a note about the right thing to do: move that to an option in run-program/
Remove a few warnings and fix some style.

Put back the dependency on fare-mop (we use its SIMPLE-PRINT-OBJECT-MIXIN, as reported by Nathan Hawkins <utsl@quic.net>).
Also, add a trivial test suite to prevent such breakage from happening again.