diff -rubB owfs-3.2p2.orig/module/owserver/src/c/owserver.c owfs-3.2p2/module/owserver/src/c/owserver.c
--- owfs-3.2p2.orig/module/owserver/src/c/owserver.c	2020-09-23 10:58:40.000000000 +0300
+++ owfs-3.2p2/module/owserver/src/c/owserver.c	2021-01-21 14:26:36.643855596 +0300
@@ -36,6 +36,8 @@
 
 #include "owserver.h"
 
+pthread_mutex_t persistence_mutex ;
+
 /* --- Prototypes ------------ */
 static void SetupAntiloop(int argc, char **argv);
 
diff -rubB owfs-3.2p2.orig/module/owserver/src/include/owserver.h owfs-3.2p2/module/owserver/src/include/owserver.h
--- owfs-3.2p2.orig/module/owserver/src/include/owserver.h	2020-09-23 10:58:40.000000000 +0300
+++ owfs-3.2p2/module/owserver/src/include/owserver.h	2021-01-21 14:26:17.634796523 +0300
@@ -19,7 +19,7 @@
 #include "ow.h"
 #include "ow_connection.h"
 
-pthread_mutex_t persistence_mutex ;
+extern pthread_mutex_t persistence_mutex ;
 #define PERSISTENCELOCK    _MUTEX_LOCK(   persistence_mutex ) ;
 #define PERSISTENCEUNLOCK  _MUTEX_UNLOCK( persistence_mutex ) ;