Fix header to include. From Kristaps Dzonsons.

lib/libc/stdlib/getsubopt.3

@@ -1,4 +1,4 @@
-.\"	$NetBSD: getsubopt.3,v 1.11 2003/08/07 16:43:40 agc Exp $
+.\"	$NetBSD: getsubopt.3,v 1.12 2009/10/19 22:38:56 joerg Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)getsubopt.3	8.1 (Berkeley) 6/9/93
 .\"
-.Dd June 9, 1993
+.Dd October 19, 2009
 .Dt GETSUBOPT 3
 .Os
 .Sh NAME
@@ -38,7 +38,7 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In stdlib.h
+.In unistd.h
 .Vt extern char *suboptarg
 .Ft int
 .Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"