diff --git a/threads.c b/threads.c
index 37c7d9c..b790d05 100644
--- a/threads.c
+++ b/threads.c
@@ -7,6 +7,7 @@
  * daniel@veillard.com
  */
 
+#define IN_LIBXML
 #include "libxml.h"
 
 #include <string.h>