Sigh. Apply a similar patch to the *other* occurrence of [^...].
diff --git a/Doc/lib/libre.tex b/Doc/lib/libre.tex
index 27d620b..f3e8468 100644
--- a/Doc/lib/libre.tex
+++ b/Doc/lib/libre.tex
@@ -234,7 +234,7 @@
%
\item[\code{\e W}]When the LOCALE flag is not specified, matches any
non-alphanumeric character; this is equivalent to the set
-\code{[\^a-zA-Z0-9_]}. With LOCALE, it will match any character
+\code{[{\^}a-zA-Z0-9_]}. With LOCALE, it will match any character
not in the set \code{[0-9_]}, and not defined as a letter
for the current locale.