Restore Makefile step for cbmc init.

Author: smowton

Makefile

@@ -7,9 +7,15 @@ clean:
 	$(MAKE) $(MAKEARGS) -C cbmc/src clean
 	$(MAKE) $(MAKEARGS) -C src clean
 
+setup-cbmc:
+  # To make a single step build, proactively do the dependency downloads:
+	$(MAKE) $(MAKEARGS) -C cbmc/src minisat2-download
+	$(MAKE) $(MAKEARGS) -C cbmc/src boost-download
+
 regression:
 ifndef single
 	python ./benchmarks/evaluator.py
 else
 	python ./benchmarks/evaluator.py -B $(single)
 endif
+