diff --git a/xmlIO.c b/xmlIO.c
index edb2389..e3c16fb 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -8,6 +8,7 @@
  * 14 Nov 2000 ht - for VMS, truncated name of long functions to under 32 char
  */
 
+#define IN_LIBXML
 #include "libxml.h"
 
 #include <string.h>