diff --git a/libraries/librewrite/rewrite-int.h b/libraries/librewrite/rewrite-int.h
index 39addce8a2..9368389ba6 100644
--- a/libraries/librewrite/rewrite-int.h
+++ b/libraries/librewrite/rewrite-int.h
@@ -47,9 +47,10 @@
 #undef strdup
 #define	strdup(x)	ber_strdup(x)
 
-/* Uncomment to use ldap pvt threads */
+#ifndef NO_THREADS
 #define USE_REWRITE_LDAP_PVT_THREADS
 #include <ldap_pvt_thread.h>
+#endif
 
 /*
  * For details, see RATIONALE.
diff --git a/libraries/librewrite/session.c b/libraries/librewrite/session.c
index 58da68fe77..bcd05c37ba 100644
--- a/libraries/librewrite/session.c
+++ b/libraries/librewrite/session.c
@@ -185,7 +185,9 @@ rewrite_session_return(
 {
 	assert( session != NULL );
 	session->ls_count--;
+#ifdef USE_REWRITE_LDAP_PVT_THREADS
 	ldap_pvt_thread_mutex_unlock( &session->ls_mutex );
+#endif /* USE_REWRITE_LDAP_PVT_THREADS */
 }
 
 /*
@@ -329,7 +331,9 @@ rewrite_session_free( void *v_session )
 {
 	struct rewrite_session	*session = (struct rewrite_session *)v_session;
 
+#ifdef USE_REWRITE_LDAP_PVT_THREADS
 	ldap_pvt_thread_mutex_lock( &session->ls_mutex );
+#endif /* USE_REWRITE_LDAP_PVT_THREADS */
 	rewrite_session_clean( v_session );
 	free( v_session );
 }