Added make clean.

Makefile

@@ -13,3 +13,8 @@ OBJ = posix_lock.o other.o LeaHeader.o sys_alloc.o dmm_init.o test.o
 
 test: $(OBJ)
 	gcc -pthread -o $@ $^ $(CFLAGS)
+
+clean:
+	-@$(RM) $(wildcard $(OBJ))
+
+.PHONY: all clean test