Fixes in 2020/ferguson2 make clobber

2020/ferguson2/Makefile

@@ -215,7 +215,7 @@ clean:
 
 clobber: clean
 	${RM} -f ${TARGET} ${ALT_TARGET}
-	${RM} -rf *.dSYM decrypted.html
+	${RM} -rf *.dSYM decrypted.html conf input output output2 
 	@-if [ -e sandwich ]; then \
 	    ${RM} -f sandwich; \
 	    echo 'ate sandwich'; \