--- src/include/postgres.h.ORIGIN	2017-02-01 07:32:04 -0600
+++ src/include/postgres.h	2017-02-01 07:32:29 -0600
@@ -44,6 +44,10 @@
 #ifndef POSTGRES_H
 #define POSTGRES_H
 
+#ifdef _AIX
+#define _LARGE_FILES 1
+#endif
+
 #include "c.h"
 #include "utils/elog.h"
 #include "utils/palloc.h"