Avoid warning from ar
diff --git a/library/Makefile b/library/Makefile
index 37ba14e..5575ded 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -85,7 +85,7 @@
 
 libmbedtls.a: $(OBJS)
 	echo "  AR    $@"
-	$(AR) r $@ $(OBJS)
+	$(AR) rc $@ $(OBJS)
 	echo "  RL    $@"
 	$(AR) s $@