diff --git a/vpi/sys_queue.c b/vpi/sys_queue.c
index adc281ec2..86ad0c6de 100644
--- a/vpi/sys_queue.c
+++ b/vpi/sys_queue.c
@@ -16,10 +16,11 @@
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "sys_priv.h"
 #include <assert.h>
 #include <inttypes.h>
 #include <stdlib.h>
+#include "sys_priv.h"
+#include "ivl_alloc.h"
 
 /*
  * The two queue types.