coll/fca: add missing #include <alloca.h>

ompi/mca/coll/fca/coll_fca_ops.c

@@ -1,12 +1,18 @@
-/**
-  Copyright (c) 2011 Mellanox Technologies. All rights reserved.
-  $COPYRIGHT$
-
-  Additional copyrights may follow
-
-  $HEADER$
+/*
+ * Copyright (c) 2011      Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2015      Research Organization for Information Science
+ *                         and Technology (RIST). All rights reserved.
+ * $COPYRIGHT$
+ *
+ * Additional copyrights may follow
+ *
+ * $HEADER$
  */
 
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
+
 #include "ompi_config.h"
 #include "ompi/constants.h"
 #include "coll_fca.h"