Bump libusual

diff --git a/lib b/lib
index e90ca270d50183d8a697caa3dd7060449d7948d3..64000c3bf99c1eb3a272bd266083ba3d033a7fcb 160000 (submodule)
--- a/lib
+++ b/lib
@@ -1 +1 @@
-Subproject commit e90ca270d50183d8a697caa3dd7060449d7948d3
+Subproject commit 64000c3bf99c1eb3a272bd266083ba3d033a7fcb