Upgrade libusual

diff --git a/lib b/lib
index 0bf97ffcba6b7ee76458d1fef520ef333d738433..7dd946ae6023574eefdb9d254faae46805c16c07 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 0bf97ffcba6b7ee76458d1fef520ef333d738433
+Subproject commit 7dd946ae6023574eefdb9d254faae46805c16c07