pmix/pmix120: add missing include file

Author: ggouaillardet

opal/mca/pmix/pmix120/pmix120_client.c

@@ -1,7 +1,7 @@
 /* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
 /*
  * Copyright (c) 2014-2015 Intel, Inc.  All rights reserved.
- * Copyright (c) 2014-2015 Research Organization for Information Science
+ * Copyright (c) 2014-2016 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * Copyright (c) 2014      Mellanox Technologies, Inc.
  *                         All rights reserved.
@@ -25,6 +25,7 @@
 
 #include "opal/hash_string.h"
 #include "opal/util/proc.h"
+#include "opal/util/argv.h"
 
 #include "opal/mca/pmix/base/base.h"
 #include "pmix120.h"