diff --git a/intl/gettextP.h b/intl/gettextP.h
index f680a9a0a1..f1aa329e47 100644
--- a/intl/gettextP.h
+++ b/intl/gettextP.h
@@ -147,6 +147,7 @@ struct loaded_domain
   /* Cache of charset conversions of the translated strings.  */
   struct converted_domain *conversions;
   size_t nconversions;
+  __libc_rwlock_define (, conversions_lock);
 
   const struct expression *plural;
   unsigned long int nplurals;