Add in a missing #include for Solaris builds.

This commit was SVN r16416.

orte/mca/pls/base/pls_base_reuse_daemon_launch.c

@@ -17,6 +17,10 @@
  *
  */
 
+#ifdef HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+
 #include "orte_config.h"
 #include "orte/orte_constants.h"