Needed for S_IRUSR and S_IWUSR.

Index: src/backend/distributed/worker/worker_sql_task_protocol.c
--- src/backend/distributed/worker/worker_sql_task_protocol.c.orig
+++ src/backend/distributed/worker/worker_sql_task_protocol.c
@@ -9,6 +9,7 @@
  *-------------------------------------------------------------------------
  */
 
+#include <sys/stat.h>
 #include "postgres.h"
 #include "funcapi.h"
 #include "pgstat.h"
