kc3-lang/kc3

diff --git a/libc3/facts.c b/libc3/facts.c
index fee9bff..fb9aa80 100644
--- a/libc3/facts.c
+++ b/libc3/facts.c
@@ -374,7 +374,7 @@ void facts_lock_unlock_w (s_facts *facts)
   assert(facts);
   facts->rwlock_count--;
   if (! facts->rwlock_count) {
-    facts->rwlock_thread = NULL;
+    facts->rwlock_thread = 0;
     if (pthread_rwlock_unlock(&facts->rwlock))
       err(1, "facts_lock_unlock_w: pthread_rwlock_unlock");
   }