libusual updated to the latest version (that is already 9 months old)

diff --git a/lib b/lib
index 7b291d464c6ff1e6aa42a17d323ee07e2b7f266d..2c1cb7f9bfa0a2a183354eb2630a3e4136d0f96b 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit 7b291d464c6ff1e6aa42a17d323ee07e2b7f266d
+Subproject commit 2c1cb7f9bfa0a2a183354eb2630a3e4136d0f96b