diff --git a/ompi/tools/mpisync/sync.c b/ompi/tools/mpisync/sync.c
index 875ece73af7..658ada2df7e 100644
--- a/ompi/tools/mpisync/sync.c
+++ b/ompi/tools/mpisync/sync.c
@@ -8,6 +8,8 @@
  * $HEADER$
  */
 
+#include "opal_config.h"
+
 #include <stdio.h>
 #include <mpi.h>
 #include <unistd.h>