.\"	$NetBSD: BUILDING.mdoc,v 1.22 2003/05/25 12:34:28 lukem Exp $
.\"
.\" Copyright (c) 2001-2003 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Todd Vierling and Luke Mewburn.
.\"
.\" 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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
.\"    contributors may be used to endorse or promote products derived
.\"    from this software without specific prior written permission.
.\"
.\" 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.
.\"
.\" NOTE: After changing this file, run "make build-docs" to generate the
.\" proper plaintext versions, and check in all BUILDING.* files!
.\"
.\" Toolchain prefix for commands
.ds toolprefix nb
.
.Dd May 25, 2003
.Dt BUILDING 8
.Os NetBSD
.
.Sh NAME
.
.Nm BUILDING
.Nd Procedure for building
.Nx
from source code.
.
.Sh STATUS
.
This document is a work-in-progress.
As such, the information described
here may not match the reality of the build system as of this writing.
Once this document is completely in sync with reality, this paragraph
will be removed.
.Pp
Discrepancies between this documentation and the current reality of
implementation are noted specially, as with the note below:
.Pp
.Em Note :
This document applies only to platforms which use the new toolchain as
indicated by the default setting of
.Sy TOOLCHAIN_MISSING
in
.Aq bsd.own.mk .
Platforms which have not yet been switched to the new toolchain should
continue building traditionally, using the notes specified in the file
.Sy UPDATING .
.
.Sh REQUIREMENTS
.
.Nx
is designed to be buildable on most POSIX-compliant host systems.
The basic build procedure is the same whether compiling
.Em natively
(on the same
.Nx
architecture) or
.Em cross compiling
(on another architecture or OS).
.Pp
This source tree contains a special subtree,
.Dq tools ,
which uses the host system to create a build toolchain for the target
architecture.
The host system must have at least C and C++
compilers in order to create the toolchain
.Nm ( make
is not required); all other tools are created as part of the
.Nx
build process.
.Pp
.Bd -ragged -offset indent
.Em Note :
A couple of host toolchain components are not yet available in the tools
directory.
Also, some tools use non-POSIX, non-ANSI C extensions
and need to be standardized.
As a result, cross-compiling from systems other than
.Nx
is not currently supported.
.Ed
.
.Sh FILES
.
.Ss Source tree layout
.
.Bl -tag -width "BUILDING.mdoc"
.It Sy doc/BUILDING.mdoc
This document (in -mdoc troff format; the original copy).
.It Sy BUILDING
This document (in plaintext).
.It Sy Makefile
The main Makefile for
.Nx ;
should only be run for native builds with an appropriately up-to-date
version of
.Nx
.Xr make 1 .
(For building from out-of-date systems or on a non-native host, see the
.Nm build.sh
shell script.)
.It Sy UPDATING
Special notes for updating from an earlier revision of
.Nx .
It is important to read this file before every build of an updated
source tree.
.It Sy build.sh
Bourne-compatible shell script used for building the host build tools
and the
.Nx
system from scratch.
Can be used for both native and cross builds, and should be used instead of
.Xr make 1
for any source tree that is updated and recompiled regularly.
.It Sy crypto/dist/ , dist/ , gnu/dist/
Sources imported verbatim from third parties, without mangling the
existing build structure.
Other source trees in
.Sy bin
through
.Sy usr.sbin
use the
.Nx
.Xr make 1
.Dq reachover
Makefile semantics when building these programs for a native host.
.It Sy distrib/ , etc/
Sources for items used when making a full release snapshot, such as
files installed in
.Sy DESTDIR Ns Pa /etc
on the destination system, boot media, and release notes.
.It Sy regress/
Regression test harness.
Can be cross-compiled, but only run natively.
.It Sy sys/
.Nx
kernel sources.
.It Sy tools/
.Dq Reachover
build structure for the host build tools.
This has a special method of determining out-of-date status.
.It Sy bin/ ... usr.sbin/
Sources to the
.Nx
userland (non-kernel) programs.
If any of these directories are missing, they will be skipped during the build.
.El
.
.Ss Build tree layout
.
The
.Nx
build tree is described in
.Xr hier 7 ,
and the release layout is described in
.Xr release 7 .
.Pp
.
.Sh CONFIGURATION
.
.Ss Environment variables
..
Several environment variables control the behaviour of
.Nx
builds.
.
.Bl -tag -width "MAKEOBJDIRPREFIX"
.
.It Sy MACHINE
Machine type.
.
.It Sy MACHINE_ARCH
Machine architecture.
.
.It Sy MAKE
Path name to invoke
.Xr make 1
as.
.
.It Sy MAKEFLAGS
Flags to invoke
.Xr make 1
with.
.
.It Sy MAKEOBJDIR
Directory to use as the
.Sy .OBJDIR
for the current directory.
Used only if
.Sy MAKEOBJDIRPREFIX
is not defined.
.Sy MAKEOBJDIR
can only be provided in the environment.
.
.It Sy MAKEOBJDIRPREFIX
Top level directory of the object directory tree.
If this is defined,
${MAKEOBJDIRPREFIX}/${.CURDIR}
is used as the
.Sy .OBJDIR
for the current directory.
The current directory may be read only.
.Sy MAKEOBJDIRPREFIX
can only be provided in the environment.
.
.El
.
.Ss \*qmake\*q variables
.
.de YorN
Can be set to
.Dq yes
or
.Dq no .
..
.de DFLT
.Pp
.Em Default :
..
.de DFLTu
.DFLT
Unset.
..
.de DFLTy
.DFLT
.Dq yes
..
.de DFLTn
.DFLT
.Dq no
..
Several variables control the behavior of
.Nx
builds.
Unless otherwise specified, these variables may be set in
either the process environment or the
.Xr make 1
configuration file specified by
.Sy MAKECONF .
.
.Bl -tag -width "MKCATPAGES"
.
.It Sy BUILDID
Identifier for the build.
The identifier will be appended to
object directory names, and can be consulted in the
.Xr make 1
configuration file in order to set additional build parameters,
such as compiler flags.
.
.It Sy DESTDIR
Directory to contain the built
.Nx
system.
If set, special options are passed to the compilation tools to
prevent their default use of the host system's
.Sy /usr/include , /usr/lib ,
and so forth.
This pathname should
.Em not
end with a slash
.Pq /
character (for installation into the system's root directory, set
.Sy DESTDIR
to an empty string).
The directory must reside on a file system which supports long file
names and hard links.
.DFLT
Empty string if
.Sy USETOOLS
is
.Dq yes ;
unset otherwise.
.Pp
.Em Note :
.Sy build.sh
will provide a default of
.Pa destdir. Ns Sy MACHINE
(in the top-level
.Sy .OBJDIR )
unless run in
.Sq expert
mode
.
.It Sy MAKECONF
The name of the
.Xr make 1
configuration file.
.Em Only settable in the process environment.
.DFLT
.Dq /etc/mk.conf
.
.It Sy MKCATPAGES
.YorN
Indicates whether preformatted plaintext manual pages will be created
during a build.
.DFLTy
.
.It Sy MKCRYPTO
.YorN
Indicates whether cryptographic code will be included in a build;
provided for the benefit of countries that do not allow strong
cryptography.
Will not affect use of the standard low-security password encryption system,
.Xr crypt 3 .
.DFLTy
.
.It Sy MKDOC
.YorN
Indicates whether system documentation destined for
.Sy DESTDIR Ns Pa /usr/share/doc
will be installed during a build.
.DFLTy
.
.It Sy MKHOSTOBJ
.YorN
If set to
.Dq yes ,
then for programs intended to be run on the compile host,
the name, release, and architecture of the host operating system
will be suffixed to the name of the object directory created by
.Dq make obj .
(This allows multiple host systems to compile NetBSD for a single target.)
If set to
.Dq no ,
then programs built to be run on the compile host will use the same
object directory names as programs built to be run on the target.
.DFLTn
.
.It Sy MKINFO
.YorN
Indicates whether GNU Info files, used for the documentation for
most of the compilation tools, will be created and installed during a
build.
.DFLTy
.
.It Sy MKLINT
.YorN
Indicates whether
.Xr lint 1
will be run against portions of the
.Nx
source code during the build, and whether lint libraries will be
installed into
.Sy DESTDIR Ns Pa /usr/libdata/lint .
.DFLTy
.
.It Sy MKMAN
.YorN
Indicates whether manual pages will be installed during a build.
.DFLTy
.
.It Sy MKNLS
.YorN
Indicates whether Native Language System locale zone files will be
compiled and installed during a build.
.DFLTy
.
.It Sy MKOBJ
.YorN
Indicates whether object directories will be created when running
.Dq make obj .
If set to
.Dq no ,
then all built files will be located inside the regular source tree.
.DFLTy
.
.It Sy MKPIC
.YorN
Indicates whether shared objects and libraries will be created and
installed during a build.
If set to
.Dq no ,
the entire built system will be statically linked.
.DFLT
Platform dependent.
As of this writing, all platforms except
.Sy sh3
default to
.Dq yes .
.
.It Sy MKPICINSTALL
.YorN
Indicates whether the
.Xr ar 1
format libraries
.Sy ( lib*_pic.a ) ,
used to generate shared libraries, are installed during a build.
.DFLTy
.
.It Sy MKPROFILE
.YorN
Indicates whether profiled libraries
.Sy ( lib*_p.a )
will be built and installed during a build.
.DFLT
.Dq yes ;
however, some platforms turn off
.Sy MKPROFILE
by default at times due to toolchain problems with profiled code.
.
.It Sy MKSHARE
.YorN
Indicates whether files destined to reside in
.Sy DESTDIR Ns Pa /usr/share
will be built and installed during a build.
If set to
.Dq no ,
then all of
.Sy MKCATPAGES , MKDOC , MKINFO , MKMAN ,
and
.Sy MKNLS
will be set to
.Dq no
unconditionally.
.DFLTy
.
.It Sy TOOLDIR
Directory to hold the host tools, once built.
This directory should be unique to a given host system and
.Nx
source tree.
(However, multiple targets may share the same
.Sy TOOLDIR ;
the target-dependent files have unique names.)  If unset, a default based
on the
.Xr uname 1
information of the host platform will be created in the
.Sy .OBJDIR
of
.Pa src/tools .
.DFLTu
.
.It Sy UNPRIVED
If set, then an unprivileged install will occur.
The user, group, permissions, and file flags, will not be set on
the installed item; instead the information will be appended to
a file called
.Pa METALOG
in
.Sy DESTDIR .
The contents of
.Pa METALOG
is used during the generation of the distribution tar files to ensure
that the appropriate file ownership is stored.
.DFLTu
.
.It Sy UPDATE
If set, then all install operations intended to write to
.Sy DESTDIR
will compare file timestamps before installing, and skip the install
phase if the destination files are up-to-date.
This also has implications on full builds (see next subsection).
.DFLTu
.
.It Sy USETOOLS
Indicates whether the tools specified by
.Sy TOOLDIR
should be used as part of a build in progress.
Must be set to
.Dq yes
if cross-compiling.
.Bl -tag -width "never"
.It Sy yes
Use the tools from
.Sy TOOLDIR .
.It Sy no
Do not use the tools from
.Sy TOOLDIR ,
but refuse to build native compilation tool components that are
version-specific for that tool.
.It Sy never
Do not use the tools from
.Sy TOOLDIR ,
even when building native tool components.
This is similar to the traditional
.Nx
build method, but does
.Em not
verify that the compilation tools in use are up-to-date enough in order
to build the tree successfully.
This may cause build or runtime problems when building the whole
.Nx
source tree.
.El
.DFLT
.Dq yes
if building all or part of a whole
.Nx
source tree (detected automatically);
.Dq no
otherwise (to preserve traditional semantics of the
.Aq bsd.*.mk
.Xr make 1
include files).
.
.El
.
.Ss \*qmake\*q variables for full builds
These variables only affect the top level
.Dq Makefile
and do not affect manually building subtrees of the
.Nx
source code.
.
.Bl -tag -width "INSTALLWORLDDIR"
.
.It Sy INSTALLWORLDDIR
Location for the
.Dq make installworld
target to install to.
.DFLT
.Dq /
.
.It Sy MKOBJDIRS
.YorN
Indicates whether object directories will be created automatically
(via a
.Dq make obj
pass) at the start of a build.
.DFLTn
.
.It Sy NBUILDJOBS
Now obsolete.
Use the 
.Xr make 1
option
.Fl j ,
instead (see below)
.DFLTu
.
.It Sy NOCLEANDIR
If set, avoids the
.Dq make cleandir
phase of a full build.
This has the effect of allowing only changed
files in a source tree to be recompiled.
This can speed up builds when updating only a few files in the tree.
.DFLTu
.
.It Sy NODISTRIBDIRS
If set, avoids the
.Dq make distrib-dirs
phase of a full build.
This skips running
.Xr mtree 8
on
.Sy DESTDIR ,
useful on systems where building as an unprivileged user, or where it is
known that the system-wide mtree files have not changed.
.DFLTu
.
.It Sy NOINCLUDES
If set, avoids the
.Dq make includes
phase of a full build.
This has the effect of preventing
.Xr make 1
from thinking that some programs are out-of-date simply because the
system include files have changed.
However, this option should not be used when updating the entire
.Nx
source tree arbitrarily; it is suggested to use
.Sy UPDATE
in that case.
.DFLTu
.
.It Sy RELEASEDIR
If set, specifies the directory to which a
.Xr release 7
layout will be written at the end of a
.Dq make release .
.DFLTu
.Pp
.Em Note :
.Sy build.sh
will provide a default of
.Pa releasedir
(in the top-level
.Sy .OBJDIR )
unless run in
.Sq expert
mode
.
.It Sy UPDATE
If set, then in addition to the effects described for UPDATE above, this
implies the effects of
.Sy NOCLEANDIR
(i.e., 
.Dq make cleandir
is avoided).
.
.El
.
.Sh BUILDING
.
.Ss \*qmake\*q command line options
This is only a summary of options available to
.Xr make 1 ;
only the options used most frequently with
.Nx
builds are listed here.
.
.Bl -tag -width "var=value"
.
.It Fl j Ar njob
Run up to
.Ar njob
.Xr make 1 
subjobs in parallel.
Makefiles should use .WAIT or have explicit dependancies 
as necessary to enforce build ordering.
If you see build failures with -j, please save complete build logs 
so the failures can be analyzed.
.
.It Fl m Ar dir
Specify the default directory for searching for system Makefile
segments, mainly the
.Aq bsd.*.mk
files.
When building any full
.Nx
source tree, this should be set to the
.Dq share/mk
directory in the source tree.
(This is set automatically when building from the top level.)
.
.It Fl n
Display the commands that would have been executed, but do not
actually execute them.
This will still cause recursion to take place.
.
.It Fl v Ar var
Print
.Xr make 1 Ns 's
idea of the value of
.Ar var .
Does not build any targets.
.
.It Em var=value
Set the variable
.Em var
to
.Em value ,
overriding any setting specified by the process environment, the
.Sy MAKECONF
configuration file, or the system Makefile segments.
.
.El
.
.Ss \*qmake\*q targets
.
These default targets may be built by running
.Xr make 1
in any subtree of the
.Nx
source code.
It is recommended that none of these be used from the top
level Makefile; as a specific exception,
.Dq make obj
and
.Dq make cleandir
are useful in that context.
.
.Bl -tag -width "dependall"
.
.It Sy all
Build programs, libraries, and preformatted documentation.
.
.It Sy clean
Remove program and library object code files.
.
.It Sy cleandir
Same as
.Sy clean ,
but also remove preformatted documentation, dependency files generated
by
.Dq make depend ,
and any other files known to be created at build time.
.Dq make distclean
may be used as a synonym, for familiarity with a similar well-known
convention.
.
.It Sy depend
Create dependency files
.Sy ( .depend )
containing more detailed information about the dependencies of source
code on header files.
Allows programs to be recompiled automatically when a dependency changes.
.
.It Sy dependall
Does a
.Dq make depend
immediately followed by a
.Dq make all .
This improves cache locality of the build since both passes read the source
files in their entirety.
.
.It Sy includes
Build and install system header files.
Typically needed before any system libraries or programs can be built.
.
.It Sy install
Install programs, libraries, and documentation into
.Sy DESTDIR .
Few files will be installed to
.Sy DESTDIR Ns Pa /dev ,
.Sy DESTDIR Ns Pa /etc ,
.Sy DESTDIR Ns Pa /root
or
.Sy DESTDIR Ns Pa /var
in order to prevent user supplied configuration data from being overwritten.
.It Sy lint
Run
.Xr lint 1
against the C source code, where appropriate, and generate
system-installed lint libraries.
.
.It Sy obj
Create object directories to be used for built files, instead of
building directly in the source tree.
.
.It Sy tags
Create
.Xr ctags 1
searchable function lists usable by the
.Xr ex 1
and
.Xr vi 1
text editors.
.
.El
.
.Ss \*qmake\*q targets for the top level
.
Additional
.Xr make 1
targets are usable specifically from the top source level to facilitate
building the entire
.Nx
source tree.
.
.Bl -tag -width "distribution"
.
.It Sy build
Build the entire
.Nx
system.
This orders portions of the source tree such that prerequisites
will be built in the proper order.
.
.It Sy distribution
Do a
.Dq make build ,
and then install a full distribution into
.Sy DESTDIR ,
including files in
.Sy DESTDIR Ns Pa /dev ,
.Sy DESTDIR Ns Pa /etc ,
.Sy DESTDIR Ns Pa /root
and
.Sy DESTDIR Ns Pa /var .
.
.It Sy buildworld
As per
.Dq make distribution ,
except that it ensures that
.Sy DESTDIR
is not the root directory.
.
.It Sy installworld
Install the distribution from
.Sy DESTDIR
to
.Sy INSTALLWORLDDIR
(which defaults to the root directory).
Ensures that
.Sy INSTALLWORLDDIR
is the not root directory if cross compiling.
.Pp
.Em Note :
It is highly recommended that you upgrade your kernel and reboot
before performing this operation.
.
.It Sy sets
Create distribution sets from
.Sy DESTDIR
into
.Sy RELEASEDIR/MACHINE Ns Pa /binary/sets .
Should be run after
.Dq make distribution
(as
.Dq make build
does not install all of the required files).
.
.It Sy sourcesets
Create source sets of the source tree into
.Sy RELEASEDIR Ns Pa /source/sets .
.
.It Sy release
Do a
.Dq make distribution ,
build kernels, distribution media, and install sets
(this as per
.Dq make sets ) ,
and
then package the system into a standard release layout as described by
.Xr release 7 .
This requires that
.Sy RELEASEDIR
be set (see above).
.
.It Sy regression-tests
Can only be run after building the regression tests in the directory
.Dq regress .
Runs the compiled regression tests on the local host.
.
.El
.
.Ss The \*qbuild.sh\*q script
.
This script file is a Bourne shell script designed to build the
entire
.Nx
system on any host with a Bourne shell in
.Sy /bin/sh ,
including many that are not POSIX compliant.
Note that if a host system's
.Sy /bin/sh
is unusually old and broken, the Korn Shell
.Sy ( /bin/ksh ) ,
if available, may be a usable alternative.
.Pp
All cross-compile builds, and most native builds, of the entire system
should make use of
.Sy build.sh
rather than just running
.Dq make .
This way, the
.Xr make 1
program will be bootstrapped properly, in case the host system has an
older or incompatible
.Dq make
program.
.Pp
When compiling the entire system via
.Sy build.sh ,
many
.Xr make 1
variables are set for you in order to help encapsulate the build
process.
In the list of options below, variables that are automatically set by
.Sy build.sh
are noted where applicable.
.
.Pp
The following operations are supported by
.Sy build.sh :
.
.Bl -tag -width "distribution"
.
.It Sy build
Build the system as per
.Dq make build .
This option implies the
.Sy obj
and
.Sy tools
operations.
.
.It Sy distribution
Build a full distribution as per
.Dq make distribution .
This option implies the
.Sy build
operation.
.
.It Sy release
Build a full release as per
.Dq make release .
This option implies the
.Sy distribution
operation.
.
.It Sy makewrapper
Create the
.Sy \*[toolprefix]make-MACHINE
wrapper.
This operation is automatically performed for any of the other
operations.
.
.It Sy obj
Perform
.Dq make obj .
.
.It Sy tools
Build and install the host tools from
.Pa src/tools .
.
.It Sy install Ns = Ns Ar idir
Install the contents of
.Sy DESTDIR
to
.Ar idir ,
using
.Dq make installworld .
.
.It Sy kernel Ns = Ns Ar kconf
Build a new kernel.
The
.Ar kconf
argument is the name of a configuration file suitable
for use by
.Xr config 8 .
If
.Ar kconf
does not contain any
.Sq /
characters, the configuration file is expected to be found in the
.Sy KERNCONFDIR
directory, which is typically
.Sy sys/arch/MACHINE/conf .
The new kernel will be built in a subdirectory of
.Sy KERNOBJDIR ,
which is typically
.Sy sys/arch/MACHINE/compile
or an associated object directory.
In order to ensure that the kernel is built using up-to-date tools,
it is strongly recommended that the tools be rebuilt (using the
.Sy tools
operation).
.
.It Sy releasekernel Ns = Ns Ar kconf
Install a
.Xr gzip 1 Ns ed
copy of the kernel built by
.Sy kernel Ns = Ns Ar kconf
into
.Sy RELEASEDIR/MACHINE Ns Pa /binary/kernel ,
usually as
.Pa netbsd- Ns Ar kconf Ns Pa .gz ,
although the
.Dq Pa netbsd
prefix is determined from the
.Dq Sy config
directives in
.Ar kconf .
.
.It Sy sets
Perform
.Dq make sets .
.
.It Sy sourcesets
Perform
.Dq make sourcesets .
.
.El
.
.Pp
The following command line options alter the behaviour of the above
operations:
The following command line options alter the behaviour of the
.Sy build.sh
operations described above:
.
.Bl -tag -width "-T tools"
.
.It Fl a Ar arch
Set the value of
.Sy MACHINE_ARCH
to
.Ar arch .
.
.It Fl B Ar buildid
Set the value of
.Sy BUILDID
to
.Ar buildid .
This will also append the build idenfitier to the name of the
.Dq make
wrapper script so that the resulting name is of the form
.Dq Sy \*[toolprefix]make-MACHINE-BUILDID .
.
.It Fl D Ar dest
Set the value of
.Sy DESTDIR
to
.Ar dest .
.
.It Fl E
Set
.Sq expert
mode.
This overrides various sanity checks, and allows:
.Sy DESTDIR
does not have to be set to a non-root path for builds,
and
.Sy UNPRIVED
does not have to be set when building as a non-root user.
.Pp
.Em Note :
It is highly recommended that you know what you are doing when
you use this option.
.
.It Fl j Ar njob
Passed through to 
.Xr make 1 .
Makefiles should use .WAIT or have explicit dependancies 
as necessary to enforce build ordering.
If you see build failures with -j, please save complete build logs 
so the failures can be analyzed.
.
.It Fl M Ar obj
Set
.Sy MAKEOBJDIRPREFIX
to
.Ar obj .
.
.It Fl m Ar mach
Set the value of
.Sy MACHINE
to
.Ar mach .
This will also override any value of
.Sy MACHINE_ARCH
in the process environment with a value deduced from
.Ar mach ,
unless
.Fl a
is specified, or
.Ar mach
is a special case listed below.
All cross builds require
.Fl m ,
but if unset on a NetBSD host, the host's value of MACHINE will be
detected and used automatically.
.Pp
Some machines support multiple values for
.Sy MACHINE_ARCH .
For a given value of
.Ar mach ,
the following
.Sy MACHINE
and
.Sy MACHINE_ARCH
values will result:
.Bl -column "evbmips-el" "MACHINE" "MACHINE_ARCH" -offset indent
.It Sy Ar mach Ta Sy "MACHINE" Ta Sy "MACHINE_ARCH"
.It evbmips Ta evbmips Ta (not set)
.It evbmips-eb Ta evbmips Ta mipseb
.It evbmips-el Ta evbmips Ta mipsel
.It evbsh3 Ta evbsh3 Ta (not set)
.It evbsh3-eb Ta evbsh3 Ta sh3eb
.It evbsh3-el Ta evbsh3 Ta sh3el
.It sbmips Ta sbmips Ta (not set)
.It sbmips-eb Ta sbmips Ta mipseb
.It sbmips-el Ta sbmips Ta mipsel
.El
.
.It Fl n
Show the commands that would be executed by
.Sy build.sh ,
but do not make any changes.
This is similar in concept to
.Dq make -n .
.
.It Fl O Ar obj
Create an appropriate transform macro for
.Sy MAKEOBJDIR
that will place the built object files under
.Ar obj .
For instance, a setting of
.Sy /usr/obj
will place build-time files under
.Sy /usr/obj/bin , /usr/obj/lib ,
and so forth.
.
.It Fl o
Set the value of
.Sy MKOBJDIRS
to
.Dq no .
Otherwise, it will be automatically set to
.Dq yes
(which is opposite to the default behaviour).
.
.It Fl R Ar rel
Set the value of
.Sy RELEASEDIR
to
.Ar rel .
.
.It Fl r
Remove the contents of
.Sy DESTDIR
and
.Sy TOOLDIR
before building (provides a clean starting point).
This will skip deleting
.Sy DESTDIR
if building on a native system to the root directory.
.
.It Fl T Ar tools
Set the value of
.Sy TOOLDIR
to
.Ar tools .
If set, the bootstrap
.Dq make
will only be rebuilt as needed (when the source files for
.Xr make 1
change).
.
.It Fl U
Set the
.Sy UNPRIVED
variable.
.
.It Fl u
Set the
.Sy UPDATE
variable.
.
.It Xo
.Fl V
.Sm off
.Ar var
.Li =
.Op Ar value
.Sm on
.Xc
Set the variable
.Ar var
to
.Ar value
(which is optional).
.
.It Fl w Ar wrapper
Create the \*[toolprefix]make wrapper script (see below) in a custom location,
specified by
.Ar wrapper .
This allows, for instance, to place the wrapper in
.Sy PATH
automatically.
Note that
.Ar wrapper
is the full name of the file, not just a directory name.
.
.El
.
.Ss The \*q\*[toolprefix]make-MACHINE\*q wrapper script
.
If using the
.Sy build.sh
script to build
.Nx ,
a
.Sy \*[toolprefix]make-MACHINE
script will be created in
.Sy TOOLDIR/bin
upon the first build to assist in building subtrees on a cross-compile
host.
.Pp
.Sy \*[toolprefix]make-MACHINE
can be invoked in lieu of
.Xr make 1 ,
and will instead call the up-to-date version of
.Dq \*[toolprefix]make
installed into
.Sy TOOLDIR/bin
with several key variables pre-set, including
.Sy MACHINE , MACHINE_ARCH ,
and
.Sy TOOLDIR .
This script can be symlinked into a directory listed in
.Sy PATH ,
or called with an absolute path.
.
.Sh EXAMPLES
.
.Bl -enum
.
.It
.Li "./build.sh tools kernel=GENERIC"
.Pp
Build a new toolchain, and use the new toolchain to
configure and build a new GENERIC kernel.
.
.It
.Li "./build.sh -U distribution"
.Pp
Using unprivileged mode,
build a complete distribution to a
.Sy DESTDIR
directory that
.Sy build.sh
selects (and will display).
.
.It
.Li "# ./build.sh -U install=/"
.Pp
As root, install to
.Pa /
the distribution that was built
by example 2.
Even though this is run as root,
.Fl U
is required so that the permissions stored in
.Sy DESTDIR Ns Pa /METALOG
are correctly applied to the files as they're copied to
.Pa / .
.
.It
.Li "./build.sh -U -u release"
.Pp
Using unprivileged mode,
build a complete release to
.Sy DESTDIR
and
.Sy RELEASEDIR
directories that
.Sy build.sh
selects (and will display).
.Sy UPDATE
.Pq Fl u
is set to prevent the
.Dq make cleandir ,
so that if this is run after example 2, it doesn't need to redo that
portion of the release build.
.El
.
.Sh OBSOLETE VARIABLES
.
.Bl -tag -width "NBUILDJOBS"
.
.It Sy NBUILDJOBS
Use the 
.Xr make 1
option
.Fl j ,
instead.
.
.It Sy USE_NEW_TOOLCHAIN
The new toolchain is now the default.
To disable, use
.Sy TOOLCHAIN_MISSING=yes .
.El
.Sh SEE ALSO
.Xr make 1 ,
.Xr hier 7 ,
.Xr release 7
.
.Sh HISTORY
.
The
.Nm build.sh
based build scheme was introduced for
.Nx 1.6
as
.Sy USE_NEW_TOOLCHAIN ,
and re-worked to
.Sy TOOLCHAIN_MISSING
after that.
.
.Sh BUGS
.
A few platforms are not yet using this build system.