This hasn't been used for anything for a long time...

src/backend/port/hpux/port-protos.h

@@ -1,32 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * port_protos.h
- *	  port-specific prototypes for HP-UX
- *
- *
- * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
- * Portions Copyright (c) 1994, Regents of the University of California
- *
- * $Id: port-protos.h,v 1.10 2001/01/24 19:43:04 momjian Exp $
- *
- *-------------------------------------------------------------------------
- */
-#ifndef PORT_PROTOS_H
-#define PORT_PROTOS_H
-
-#include <sys/resource.h>
-#include "dl.h"
-
-#include "utils/dynamic_loader.h"
-
-/* dynloader.c */
-
-/* pg_dl{open,close,sym} prototypes are in utils/dynamic_loader.h */
-
-/* port.c */
-
-extern int	init_address_fixup(void);
-extern double rint(double x);
-extern double cbrt(double x);
-
-#endif	 /* PORT_PROTOS_H */