refresh libusual

diff --git a/lib b/lib
index 7250ab4641689ff32853f198702c35b9f8609f56..7d7a4af1cbac3fa4338e4c7aefcb680f88337a64 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 7250ab4641689ff32853f198702c35b9f8609f56
+Subproject commit 7d7a4af1cbac3fa4338e4c7aefcb680f88337a64