Add a default clean target
diff --git a/tests/Makefile b/tests/Makefile
index 8ad304d..3c604cd 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -10,7 +10,8 @@
 	@echo
 	(cd ..; tests/busybox.REGRESS.sh)
 
-clean::
+clean:
+	rm -f *.o
 
 distclean: clean