Import unmodified NetBSD libc in trunk

This patch imports the unmodified current version of NetBSD libc.
The NetBSD includes are in /nbsd_include, while the libc code itself is 
split between lib/nbsd_libc and common/lib/libc.

lib/nbsd_libc/stdlib/unlockpt.3

@@ -0,0 +1,86 @@
+.\" $NetBSD: unlockpt.3,v 1.4 2008/04/30 13:10:51 martin Exp $
+.\"
+.\" Copyright (c) 2004 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Christos Zoulas.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd May 25, 2004
+.Dt UNLOCKPT 3
+.Os
+.Sh NAME
+.Nm unlockpt
+.Nd unlock the slave pseudo-terminal device
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In stdlib.h
+.Ft int
+.Fn unlockpt "int fildes"
+.Sh DESCRIPTION
+The
+.Fn unlockpt
+unlocks access to the pseudo-terminal device corresponding to the
+master pseudo-terminal device associated with
+.Fa fildes .
+Conforming applications must call this function before opening the
+slave pseudo-terminal device.
+.Sh RETURN VALUES
+If successful,
+.Fn unlockpt
+returns 0; otherwise a value of \-1 is returned and
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+The
+.Fn unlockpt
+function will fail if:
+.Bl -tag -width Er
+.It Bq Er EACCESS
+the corresponding pseudo-terminal device could not be accessed.
+.It Bq Er EBADF
+.Fa fildes
+is not a valid descriptor.
+.It Bq Er EINVAL
+.Fa fildes
+is not associated with a master pseudo-terminal device.
+.El
+.Sh NOTES
+In
+.Nx
+.Fn unlockpt
+does nothing.
+.Sh SEE ALSO
+.Xr ioctl 2 ,
+.Xr grantpt 3 ,
+.Xr posix_openpt 3 ,
+.Xr ptsname 3
+.Sh STANDARDS
+The
+.Fn unlockpt
+function conforms to
+.St -p1003.1-2001 .
+Its first release was in
+.St -xpg4.2 .