Annotation of wikisrc/guide/build.mdwn, revision 1.2

1.1       jdf         1: # Crosscompiling NetBSD with build.sh
                      2: 
1.2     ! jdf         3: When targeting a product for an embedded platform, it's not feasible to have all
        !             4: the development tools available on that same platform. Instead, some method of
        !             5: crosscompiling is usually used today. NetBSD 1.6 and forward comes with a
        !             6: framework to build both the operating system's kernel and the whole userland for
        !             7: either the same platform that the compiler runs on, or for a different platform,
        !             8: using crosscompiling. Crosscompiling requires assembler, linker, compiler etc.
        !             9: to be available and built for the target platform. The new build scheme will
        !            10: take care of creating these tools for a given platform, and make them available
1.1       jdf        11: ready to use to do development work.
                     12: 
1.2     ! jdf        13: In this chapter, we will show how to use `build.sh` to first create a
        !            14: crosscompiling toolchain, including cross-compiler, cross-assembler,
        !            15: cross-linker and so on. While native kernel builds are covered in [[Compiling
        !            16: the kernel|guide/kernel]], these tools are then used to manually configure and
        !            17: crosscompile a kernel for a different platform, and then show how to use
        !            18: `build.sh` as a convenient alternative. After that works, the whole NetBSD
        !            19: userland will be compiled and packed up in the format of a NetBSD release. In
        !            20: the examples, we will use the Sun UltraSPARC (*sparc64*) 64-bit platform as
        !            21: target platform, any other platform supported by NetBSD can be targetted as well
1.1       jdf        22: specifying its name (see `/usr/src/sys/arch`).
                     23: 
1.2     ! jdf        24: Before starting, take note that it is assumed that the NetBSD sources from the
1.1       jdf        25: `netbsd-4-0` branch are available in `/usr/src` as described in
                     26: [[Obtaining the sources|guide/fetch]].
                     27: 
1.2     ! jdf        28: A more detailed description of the `build.sh` framework can be found in Luke
        !            29: Mewburn and Matthew Green's
        !            30: [paper](http://www.mewburn.net/luke/papers/build.sh.pdf) and their
        !            31: [presentation](http://www.mewburn.net/luke/talks/bsdcon-2003/index.html) from
1.1       jdf        32: BSDCon 2003 as well as in `/usr/src/BUILDING`.
                     33: 
                     34: ## Building the crosscompiler
                     35: 
1.2     ! jdf        36: The first step to do cross-development is to get all the necessary tools
        !            37: available. In NetBSD terminology, this is called the "toolchain", and it
1.1       jdf        38: includes BSD-compatible
                     39: [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-current),
1.2     ! jdf        40: C/C++ compilers, linker, assembler,
        !            41: [config(8)](http://netbsd.gw.com/cgi-bin/man-cgi?config+8+NetBSD-current),
        !            42: as well as a fair number of tools that are only required when crosscompiling a
1.1       jdf        43: full NetBSD release, which we won't cover here.
                     44: 
1.2     ! jdf        45: The command to create the crosscompiler is quite simple, using NetBSD's new
        !            46: `src/build.sh` script. Please note that all the commands here can be run as
1.1       jdf        47: normal (non-root) user:
                     48: 
                     49:     $ cd /usr/src
                     50:     $ ./build.sh -m sparc64 tools
                     51: 
1.2     ! jdf        52: Make sure that the directory `/usr/obj` does exist, or add a `-O` option to the
1.1       jdf        53: build.sh call, redirecting the object directory someplace else.
                     54: 
1.2     ! jdf        55: If the tools have been built previously and they only need updated, then the
1.1       jdf        56: update option `-u` can be used to only rebuild tools that have changed:
                     57: 
                     58:     $ ./build.sh -u -m sparc64 tools
                     59: 
1.2     ! jdf        60: When the tools are built, information about them and several environment
1.1       jdf        61: variables is printed out:
                     62: 
                     63:     ...
                     64:     ===> build.sh started: Thu Dec  2 22:18:11 CET 2007
                     65:     ===> build.sh ended:   Thu Dec  2 22:28:22 CET 2007
                     66:     ===> Summary of results:
                     67:              build.sh command: ./build.sh -m sparc64 tools
                     68:              build.sh started: Thu Dec  2 22:18:11 CET 2007
                     69:              No nonexistent/bin/nbmake, needs building.
                     70:              Bootstrapping nbmake
                     71:              MACHINE:          sparc64
                     72:              MACHINE_ARCH:     sparc64
                     73:              TOOLDIR path:     /usr/src/tooldir.NetBSD-4.0-i386
                     74:              DESTDIR path:     /usr/src/destdir.sparc64
                     75:              RELEASEDIR path:  /usr/src/releasedir
                     76:              Created /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake
                     77:              makewrapper:      /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake-sparc64
                     78:              Updated /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake-sparc64
                     79:              Tools built to /usr/src/tooldir.NetBSD-4.0-i386
                     80:              build.sh started: Thu Dec  2 22:18:11 CET 2007
                     81:              build.sh ended:   Thu Dec  2 22:28:22 CET 2007
1.2     ! jdf        82:     ===> .
1.1       jdf        83: 
1.2     ! jdf        84: During the build, object directories are used consistently, i.e. special
        !            85: directories are kept that keep the platform-specific object files and compile
        !            86: results. In our example, they will be kept in directories named `obj.sparc64` as
1.1       jdf        87: we build for UltraSPARC as target platform.
                     88: 
1.2     ! jdf        89: The toolchain itself is part of this, but as it's hosted and compiled for a i386
        !            90: system, it will get placed in its own directory indicating where to cross-build
1.1       jdf        91: from. Here's where our crosscompiler tools are located:
                     92: 
                     93:     $ pwd
                     94:     /usr/src
                     95:     $ ls -d tooldir.*
                     96:     tooldir.NetBSD-4.0-i386
                     97: 
1.2     ! jdf        98: So the general rule of thumb is for a given `host` and `target` system
        !            99: combination, the crosscompiler will be placed in the `src/tooldir.host`
        !           100: directory by default. A full list of all tools created for crosscompiling the
1.1       jdf       101: whole NetBSD operating system includes:
                    102: 
                    103:     $ ls tooldir.NetBSD-4.0-i386/bin/
                    104:     nbasn1_compile          nbmakefs                nbzic
                    105:     nbcap_mkdb              nbmakeinfo              sparc64--netbsd-addr2li
                    106:     nbcat                   nbmakewhatis            sparc64--netbsd-ar
                    107:     nbcksum                 nbmenuc                 sparc64--netbsd-as
                    108:     nbcompile_et            nbmkcsmapper            sparc64--netbsd-c++
                    109:     nbconfig                nbmkdep                 sparc64--netbsd-c++filt
                    110:     nbcrunchgen             nbmkesdb                sparc64--netbsd-cpp
                    111:     nbctags                 nbmklocale              sparc64--netbsd-dbsym
                    112:     nbdb                    nbmknod                 sparc64--netbsd-g++
                    113:     nbeqn                   nbmktemp                sparc64--netbsd-g77
                    114:     nbfgen                  nbmsgc                  sparc64--netbsd-gcc
                    115:     nbfile                  nbmtree                 sparc64--netbsd-gcc-3.3
                    116:     nbgencat                nbnroff                 sparc64--netbsd-gccbug
                    117:     nbgroff                 nbpax                   sparc64--netbsd-gcov
                    118:     nbhexdump               nbpic                   sparc64--netbsd-ld
                    119:     nbhost-mkdep            nbpwd_mkdb              sparc64--netbsd-lint
                    120:     nbindxbib               nbrefer                 sparc64--netbsd-mdsetim
                    121:     nbinfo                  nbrpcgen                sparc64--netbsd-nm
                    122:     nbinfokey               nbsoelim                sparc64--netbsd-objcopy
                    123:     nbinstall               nbstat                  sparc64--netbsd-objdump
                    124:     nbinstall-info          nbsunlabel              sparc64--netbsd-ranlib
                    125:     nbinstallboot           nbtbl                   sparc64--netbsd-readelf
                    126:     nblex                   nbtexi2dvi              sparc64--netbsd-size
                    127:     nblorder                nbtexindex              sparc64--netbsd-strings
                    128:     nbm4                    nbtsort                 sparc64--netbsd-strip
                    129:     nbmake                  nbuudecode
1.2     ! jdf       130:     nbmake-sparc64          nbyacc
1.1       jdf       131: 
1.2     ! jdf       132: As you can see, most of the tools that are available native on NetBSD are
        !           133: present with some program prefix to identify the target platform for tools that
1.1       jdf       134: are specific to a certain target platform.
                    135: 
1.2     ! jdf       136: One important tool that should be pointed out here is `nbmake-sparc64`. This is
        !           137: a shell wrapper for a BSD compatible
        !           138: [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-5.0.1+i386) command
        !           139: that's setup to use all the right commands from the crosscompiler toolchain.
        !           140: Using this wrapper instead of `/usr/bin/make` allows crosscompiling programs
        !           141: that were written using the NetBSD Makefile infrastructure (see `src/share/mk`).
        !           142: We will use this
        !           143: [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-5.0.1+i386) wrapper
1.1       jdf       144: in a second to cross compile the kernel!
                    145: 
                    146: ## Configuring the kernel manually
                    147: 
1.2     ! jdf       148: Now that we have a working crosscompiler available, the "usual" steps for
        !           149: building a kernel are needed - create a kernel config file, run
        !           150: [config(1)](http://netbsd.gw.com/cgi-bin/man-cgi?config+1+NetBSD-5.0.1+i386),
        !           151: then build. As the
        !           152: [config(1)](http://netbsd.gw.com/cgi-bin/man-cgi?config+1+NetBSD-5.0.1+i386)
        !           153: program used to create header files and Makefile for a kernel build is platform
        !           154: specific, we need to use the `nbconfig` program that's part of our new
        !           155: toolchain. That aside, the procedure is just as like compiling a "native" NetBSD
1.1       jdf       156: kernel. Commands involved here are:
                    157: 
                    158:     $ cd /usr/src/sys/arch/sparc64/conf
                    159:     $ cp GENERIC MYKERNEL
                    160:     $ vi MYKERNEL
                    161:     $ /usr/src/tooldir.NetBSD-4.0-i386/bin/nbconfig MYKERNEL
                    162: 
1.2     ! jdf       163: That's all. This command has created a directory `../compile/MYKERNEL` with a
        !           164: number of header files defining information about devices to compile into the
        !           165: kernel, a Makefile that is setup to build all the needed files for the kernel,
1.1       jdf       166: and link them together.
                    167: 
                    168: ## Crosscompiling the kernel manually
                    169: 
1.2     ! jdf       170: We have all the files and tools available to crosscompile our UltraSPARC-based
        !           171: kernel from our Intel-based host system, so let's get to it! After changing in
        !           172: the directory created in the previous step, we need to use the crosscompiler
        !           173: toolchain's `nbmake-sparc64` shell wrapper, which just calls make(1) with all
1.1       jdf       174: the necessary settings for crosscompiling for a sparc64 platform:
                    175: 
                    176:     $ cd ../compile/MYKERNEL/
                    177:     $ /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake-sparc64 depend
                    178:     $ /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake-sparc64
                    179: 
                    180: This will churn away a bit, then spit out a kernel:
                    181: 
                    182:     ...
                    183:        text    data     bss     dec     hex filename
                    184:     5016899  163728  628752 5809379  58a4e3 netbsd
                    185:     $ ls -l netbsd
                    186:     -rwxr-xr-x  1 feyrer  666  5874663 Dec  2 23:17 netbsd
                    187:     $ file netbsd
1.2     ! jdf       188:     netbsd: ELF 64-bit MSB executable, SPARC V9, version 1 (SYSV), statically linked, not stripped
1.1       jdf       189: 
1.2     ! jdf       190: Now the kernel in the file `netbsd` can either be transferred to a UltraSPARC
        !           191: machine (via NFS, FTP, scp, etc.) and booted from a possible harddisk, or
1.1       jdf       192: directly from our cross-development machine using NFS.
                    193: 
1.2     ! jdf       194: After configuring and crosscompiling the kernel, the next logical step is to
        !           195: crosscompile the whole system, and bring it into a distribution-ready format.
        !           196: Before doing so, an alternative approach to crosscompiling a kernel will be
        !           197: shown in the next section, using the `build.sh` script to do configuration and
1.1       jdf       198: crosscompilation of the kernel in one step.
                    199: 
                    200: ## Crosscompiling the kernel with build.sh
                    201: 
1.2     ! jdf       202: A cross compiled kernel can be done manually as described in the previous
1.1       jdf       203: sections, or by the easier method of using `build.sh`, which will be shown here.
                    204: 
                    205: Preparation of the kernel config file is the same as described above:
                    206: 
                    207:     $ cd /usr/src/sys/arch/sparc64/conf
                    208:     $ cp GENERIC MYKERNEL
1.2     ! jdf       209:     $ vi MYKERNEL
1.1       jdf       210: 
1.2     ! jdf       211: Then edit `MYKERNEL` and once finished, all that needs to be done is to use
        !           212: `build.sh` to build the kernel (it will also configure it, running the steps
1.1       jdf       213: shown above):
                    214: 
                    215:     $ cd /usr/src
                    216:     $ ./build.sh -u -m sparc64 kernel=MYKERNEL
                    217: 
1.2     ! jdf       218: Notice that update (`-u`) was specified, the tools are already built, there is
        !           219: no reason to rebuild all of the tools. Once the kernel is built, `build.sh` will
1.1       jdf       220: print out the location of it along with other information:
                    221: 
                    222:     ...
                    223:     ===> Summary of results:
                    224:              build.sh command: ./build.sh -u -m sparc64 kernel=MYKERNEL
                    225:              build.sh started: Thu Dec  2 23:30:02 CET 2007
                    226:              No nonexistent/bin/nbmake, needs building.
                    227:              Bootstrapping nbmake
                    228:              MACHINE:          sparc64
                    229:              MACHINE_ARCH:     sparc64
                    230:              TOOLDIR path:     /usr/src/tooldir.NetBSD-4.0-i386
                    231:              DESTDIR path:     /usr/src/destdir.sparc64
                    232:              RELEASEDIR path:  /usr/src/releasedir
                    233:              Created /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake
                    234:              makewrapper:      /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake-sparc64
                    235:              Updated /usr/src/tooldir.NetBSD-4.0-i386/bin/nbmake-sparc64
                    236:              Building kernel without building new tools
                    237:              Building kernel:  MYKERNEL
                    238:              Build directory:  /usr/src/sys/arch/sparc64/compile/obj.sparc64/GENERIC
                    239:              Kernels built from MYKERNEL:
                    240:               /usr/src/sys/arch/sparc64/compile/obj.sparc64/MYKERNEL/netbsd
                    241:              build.sh started: Thu Dec  2 23:30:02 CET 2007
                    242:              build.sh ended:   Thu Dec  2 23:38:22 CET 2007
1.2     ! jdf       243:     ===> .
1.1       jdf       244: 
1.2     ! jdf       245: The path to the kernel built is of interest here:
        !           246: `/usr/src/sys/arch/sparc64/compile/obj.sparc64/MYKERNEL/netbsd`, it can be used
1.1       jdf       247: the same way as described above.
                    248: 
                    249: ## Crosscompiling the userland
                    250: 
1.2     ! jdf       251: By now it is probably becoming clear that the toolchain actually works in
        !           252: stages. First the crosscompiler is built, then a kernel. Since `build.sh` will
        !           253: attempt to rebuild the tools at every invocation, using `update` saves time. It
        !           254: is probably also clear that outside of a few options, the `build.sh` semantics
        !           255: are basically `build.sh command`. So, it stands to reason that building the
1.1       jdf       256: whole userland and/or a release is a matter of using the right commands.
                    257: 
1.2     ! jdf       258: It should be no surprise that building and creating a release would look like
1.1       jdf       259: the following:
                    260: 
                    261:     $ ./build.sh -U -u -m sparc64 release
                    262: 
1.2     ! jdf       263: These commands will compile the full NetBSD userland and put it into a
        !           264: destination directory, and then build a release from it in a release directory.
        !           265: The `-U` switch is added here for an *unprivileged* build, i.e. one that's
        !           266: running as normal user and not as root. As no further switches to `build.sh`
        !           267: were given nor any environment variables were set, the defaults of
        !           268: `DESTDIR=/usr/src/destdir.sparc64` and `RELEASEDIR=/usr/src/releasedir` are
1.1       jdf       269: used, as shown in the `build.sh`-output above.
                    270: 
                    271: ## Crosscompiling the X Window System
                    272: 
1.2     ! jdf       273: The NetBSD project has its own copy of the X Window System's source which is
        !           274: currently based on XFree86 version 4, and which contains changes to make X going
        !           275: on as many of the platforms supported by NetBSD as possible. Due to this, it is
        !           276: desirable to use the X Window System version available from and for NetBSD,
        !           277: which can also be crosscompiled much like the kernel and base system. To do so,
        !           278: the xsrc sources must be checked out from CVS into `/usr/xsrc` just as src
1.1       jdf       279: and pkgsrc were as described in [[Obtaining the sources|guide/fetch]].
                    280: 
1.2     ! jdf       281: After this, X can be crosscompiled for the target platform by adding the `-x`
1.1       jdf       282: switch to build.sh, e.g. when creating a full release:
                    283: 
                    284:     $ ./build.sh -U -x -u -m sparc64 release
                    285: 
1.2     ! jdf       286: The `-U` flag for doing unprivileged (non-root) builds and the `-u` flag for not
        !           287: removing old files before building as well as the `-m arch` option to define the
        !           288: target architecture have already been introduced, and the `-x` option to also
1.1       jdf       289: (cross)compile xsrc is another option.
                    290: 
                    291: ## Changing build behaviour
                    292: 
1.2     ! jdf       293: Similar to the old, manual building method, the new toolchain has a lot of
        !           294: variables that can be used to direct things like where certain files go, what
        !           295: (if any) tools are used and so on. A look in `src/BUILDING` covers most of them.
        !           296: In this section some examples of changing default settings are given, each
1.1       jdf       297: following its own ways.
                    298: 
                    299: ### Changing the Destination Directory
                    300: 
1.2     ! jdf       301: Many people like to track NetBSD-current and perform cross compiles of
        !           302: architectures that they use. The logic for this is simple, sometimes a new
        !           303: feature or device becomes available and someone may wish to use it. By keeping
        !           304: track of changes and building every now and again, one can be assured that these
1.1       jdf       305: architectures can build their own release.
                    306: 
1.2     ! jdf       307: It is reasonable to assume that if one is tracking and building for more than
        !           308: one architecture, they might want to keep the builds in a different location
        !           309: than the default. There are two ways to go about this, either use a script to
        !           310: set the new DESTDIR, or simply do so interactively. In any case, it can be set
1.1       jdf       311: the same way as any other variable (depending on your shell of course).
                    312: 
                    313: For bash, the Bourne or Korn shell, this is:
                    314: 
                    315:     $ export DESTDIR=/usr/builds/sparc64
                    316: 
                    317: For tcsh and the C shell, the command is:
                    318: 
                    319:     $ setenv DESTDIR /usr/builds/sparc64
                    320: 
1.2     ! jdf       321: Simple enough. When the build is run, the binaries and files will be sent to
1.1       jdf       322: `/usr/builds`.
                    323: 
                    324: ### Static Builds
                    325: 
1.2     ! jdf       326: The NetBSD toolchain builds and links against shared libraries by default. Many
        !           327: users still prefer to be able to link statically. Sometimes a small system can
        !           328: be created without having shared libraries, which is a good example of doing a
        !           329: full static build. If a particular build machine will always need one
        !           330: environment variable set in a particular way, then it is easiest to simply add
1.1       jdf       331: the changed setting to `/etc/mk.conf`.
                    332: 
1.2     ! jdf       333: To make sure a build box always builds statically, simply add the following line
1.1       jdf       334: to `/etc/mk.conf`:
                    335: 
                    336:     LDSTATIC=-static
                    337: 
                    338: ### Using build.sh options
                    339: 
1.2     ! jdf       340: Besides variables in environment and `/etc/mk.conf`, the build process can be
        !           341: influenced by a number of switches to the `build.sh` script itself, as we have
        !           342: already seen when forcing unprivileged (non-root) builds, selecting the target
        !           343: architecture or preventing deletion of old files before the build. All these
1.1       jdf       344: options can be listed by running `build.sh -h`:
                    345: 
                    346:     $ cd /usr/src
                    347:     $ build.sh -h
                    348:     Usage: build.sh [-EnorUux] [-a arch] [-B buildid] [-D dest] [-j njob]
                    349:             [-M obj] [-m mach] [-N noisy] [-O obj] [-R release] [-T tools]
                    350:             [-V var=[value]] [-w wrapper] [-X x11src] [-Z var]
                    351:             operation [...]
                    352:     
                    353:      Build operations (all imply "obj" and "tools"):
                    354:         build               Run "make build".
                    355:         distribution        Run "make distribution" (includes DESTDIR/etc/ files).
                    356:         release             Run "make release" (includes kernels and distrib media).
                    357:     
                    358:      Other operations:
                    359:         help                Show this message and exit.
                    360:         makewrapper         Create nbmake-${MACHINE} wrapper and nbmake.
                    361:                             Always performed.
                    362:         obj                 Run "make obj".  [Default unless -o is used]
                    363:         tools               Build and install tools.
                    364:         install=idir        Run "make installworld" to `idir' to install all sets
                    365:                 except `etc'.  Useful after "distribution" or "release"
                    366:         kernel=conf         Build kernel with config file `conf'
                    367:         releasekernel=conf  Install kernel built by kernel=conf to RELEASEDIR.
                    368:         sets                Create binary sets in RELEASEDIR/MACHINE/binary/sets.
                    369:                 DESTDIR should be populated beforehand.
                    370:         sourcesets          Create source sets in RELEASEDIR/source/sets.
                    371:         params              Display various make(1) parameters.
                    372:     
                    373:      Options:
                    374:         -a arch     Set MACHINE_ARCH to arch.  [Default: deduced from MACHINE]
                    375:         -B buildId  Set BUILDID to buildId.
                    376:         -D dest     Set DESTDIR to dest.  [Default: destdir.MACHINE]
                    377:         -E          Set "expert" mode; disables various safety checks.
                    378:                     Should not be used without expert knowledge of the build system.
                    379:         -j njob     Run up to njob jobs in parallel; see make(1) -j.
                    380:         -M obj      Set obj root directory to obj; sets MAKEOBJDIRPREFIX.
                    381:                     Unsets MAKEOBJDIR.
                    382:         -m mach     Set MACHINE to mach; not required if NetBSD native.
                    383:         -N noisy    Set the noisyness (MAKEVERBOSE) level of the build:
                    384:                 0   Quiet
                    385:                 1   Operations are described, commands are suppressed
                    386:                 2   Full output
                    387:             [Default: 2]
                    388:         -n          Show commands that would be executed, but do not execute them.
                    389:         -O obj      Set obj root directory to obj; sets a MAKEOBJDIR pattern.
                    390:                     Unsets MAKEOBJDIRPREFIX.
                    391:         -o          Set MKOBJDIRS=no; do not create objdirs at start of build.
                    392:         -R release  Set RELEASEDIR to release.  [Default: releasedir]
                    393:         -r          Remove contents of TOOLDIR and DESTDIR before building.
                    394:         -T tools    Set TOOLDIR to tools.  If unset, and TOOLDIR is not set in
                    395:                     the environment, nbmake will be (re)built unconditionally.
                    396:         -U          Set MKUNPRIVED=yes; build without requiring root privileges,
                    397:                 install from an UNPRIVED build with proper file permissions.
                    398:         -u          Set MKUPDATE=yes; do not run "make clean" first.
                    399:             Without this, everything is rebuilt, including the tools.
                    400:         -V v=[val]  Set variable `v' to `val'.
                    401:         -w wrapper  Create nbmake script as wrapper.
                    402:                     [Default: ${TOOLDIR}/bin/nbmake-${MACHINE}]
                    403:         -X x11src   Set X11SRCDIR to x11src.  [Default: /usr/xsrc]
                    404:         -x          Set MKX11=yes; build X11R6 from X11SRCDIR
1.2     ! jdf       405:         -Z v        Unset ("zap") variable `v'.
1.1       jdf       406: 
1.2     ! jdf       407: As can be seen, a number of switches can be set to change the standard build
        !           408: behaviour. A number of them has already been introduced, others can be set as
1.1       jdf       409: appropriate.
                    410: 
                    411: ### make(1) variables used during build
                    412: 
1.2     ! jdf       413: Several variables control the behaviour of NetBSD builds. Unless otherwise
        !           414: specified, these variables may be set in either the process environment or in
        !           415: the [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-5.0.1+i386)
        !           416: configuration file specified by `MAKECONF`. For a definitive list of these
        !           417: options, see `BUILDING` and `share/mk/bsd.README` files in the toplevel source
1.1       jdf       418: directory.
                    419: 
1.2     ! jdf       420:  * *BUILDID* -- Identifier for the build. The identifier will be appended to
        !           421:    object directory names, and can be consulted in the
        !           422:    [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-5.0.1+i386)
        !           423:    configuration file in order to set additional build parameters, such as
1.1       jdf       424:    compiler flags.
                    425: 
1.2     ! jdf       426:  * *DESTDIR* -- Directory to contain the built NetBSD system. If set, special
        !           427:    options are passed to the compilation tools to prevent their default use of
        !           428:    the host system's `/usr/include`, `/usr/lib`, and so forth. This pathname
        !           429:    should not end with a slash (/) character (For installation into the system's
        !           430:    root directory, set `DESTDIR` to an empty string). The directory must reside
1.1       jdf       431:    on a filesystem which supports long filenames and hard links.
                    432: 
1.2     ! jdf       433:    Defaults to an empty string if `USETOOLS` is `yes`; unset otherwise. Note:
        !           434:    `build.sh` will provide a default (destdir.MACHINE in the top-level
1.1       jdf       435:    `.OBJDIR`) unless run in `expert` mode.
                    436: 
1.2     ! jdf       437:  * *EXTERNAL\_TOOLCHAIN* -- If defined by the user, points to the root of an
        !           438:    external toolchain (e.g. `/usr/local/gnu`). This enables the cross-build
        !           439:    framework even when default toolchain is not available (see
1.1       jdf       440:    `TOOLCHAIN_MISSING` below).
                    441: 
                    442:    Default: Unset
                    443: 
                    444:  * *MAKEVERBOSE* -- The verbosity of build messages. Supported values:
                    445: 
                    446:     * `0` -- No descriptive messages are shown.
                    447:     * `1` -- Descriptive messages are shown.
1.2     ! jdf       448:        * `2` -- Descriptive messages are shown (prefixed with a '\#') and command
1.1       jdf       449:          output is not suppressed.
                    450:    
                    451:    Default: 2
                    452: 
1.2     ! jdf       453:  * *MKCATPAGES* -- Can be set to `yes` or `no`. Indicates whether preformatted
1.1       jdf       454:    plaintext manual pages will be created during a build.
                    455: 
                    456:    Default: `yes`
                    457: 
1.2     ! jdf       458:  * *MKCRYPTO* -- Can be set to `yes` or `no`. Indicates whether cryptographic
        !           459:    code will be included in a build; provided for the benefit of countries that
        !           460:    do not allow strong cryptography. Will not affect the standard low-security
        !           461:    password encryption system,
1.1       jdf       462:    [crypt(3)](http://netbsd.gw.com/cgi-bin/man-cgi?crypt+3+NetBSD-5.0.1+i386).
                    463: 
                    464:    Default: `yes`
                    465: 
1.2     ! jdf       466:  * *MKDOC* -- Can be set to `yes` or `no`. Indicates whether system
        !           467:    documentation destined for `DESTDIR``/usr/share/doc` will be installed during
1.1       jdf       468:    a build.
                    469: 
                    470:    Default: `yes`
                    471: 
1.2     ! jdf       472:  * *MKHOSTOBJ* -- Can be set to `yes` or `no`. If set to `yes`, then for
        !           473:    programs intended to be run on the compile host, the name, release and
        !           474:    architecture of the host operating system will be suffixed to the name of the
        !           475:    object directory created by `make obj`. This allows for multiple host systems
        !           476:    to compile NetBSD for a single target. If set to `no`, then programs built to
        !           477:    be run on the compile host will use the same object directory names as
1.1       jdf       478:    programs built to be run on the target.
                    479: 
                    480:    Default: `no`
                    481: 
1.2     ! jdf       482:  * *MKINFO* -- Can be set to `yes` or `no`. Indicates whether GNU info files,
        !           483:    used for the documentation of most of the compilation tools, will be created
1.1       jdf       484:    and installed during a build.
                    485: 
                    486:    Default: `yes`
                    487: 
1.2     ! jdf       488:  * *MKLINT* -- Can be set to `yes` or `no`. Indicates whether
        !           489:    [lint(1)](http://netbsd.gw.com/cgi-bin/man-cgi?lint+1+NetBSD-5.0.1+i386) will
        !           490:    be run against portions of the NetBSD source code during the build, and
1.1       jdf       491:    whether lint libraries will be installed into `DESTDIR``/usr/libdata/lint`
                    492: 
                    493:    Default: `yes`
                    494: 
1.2     ! jdf       495:  * *MKMAN* -- Can be set to `yes` or `no`. Indicates whether manual pages will
1.1       jdf       496:    be installed during a build.
                    497: 
                    498:    Default: `yes`
                    499: 
1.2     ! jdf       500:  * *MKNLS* -- Can be set to `yes` or `no`. Indicates whether Native Language
1.1       jdf       501:    System locale zone files will be compiled and installed during a build.
                    502: 
                    503:    Default: `yes`
                    504: 
1.2     ! jdf       505:  * *MKOBJ* -- Can be set to `yes` or `no`. Indicates whether object directories
        !           506:    will be created when running `make obj`. If set to `no`, then all built files
1.1       jdf       507:    will be located inside the regular source tree.
                    508: 
                    509:    Default: `yes`
                    510: 
1.2     ! jdf       511:  * *MKPIC* -- Can be set to `yes` or `no`. Indicates whether shared objects and
        !           512:    libraries will be created and installed during a build. If set to `no`, the
1.1       jdf       513:    entire build will be statically linked.
                    514: 
                    515:    Default: Platform dependent. As of this writing, all platforms except sh3 default to `yes`
                    516: 
1.2     ! jdf       517:  * *MKPICINSTALL* -- Can be set to `yes` or `no`. Indicates whether the
        !           518:    [ar(1)](http://netbsd.gw.com/cgi-bin/man-cgi?ar+1+NetBSD-5.0.1+i386) format
        !           519:    libraries (`lib*_pic.a`), used to generate shared libraries, are installed
1.1       jdf       520:    during a build.
                    521: 
                    522:    Default: `yes`
                    523: 
1.2     ! jdf       524:  * *MKPROFILE* -- Can be set to `yes` or `no`. Indicates whether profiled
1.1       jdf       525:    libraries (`lib*_p.a`) will be built and installed during a build.
                    526: 
1.2     ! jdf       527:    Default: `yes`; however, some platforms turn off `MKPROFILE` by default at
1.1       jdf       528:    times due to toolchain problems with profiled code.
                    529: 
1.2     ! jdf       530:  * *MKSHARE* -- Can be set to `yes` or `no`. Indicates whether files destined to
        !           531:    reside in `DESTDIR/usr/share` will be built and installed during a build.
        !           532:    If set to `no`, then all of `MKCATPAGES`, `MKDOC`, `MKINFO`, `MKMAN` and
1.1       jdf       533:    `MKNLS` will be set to `no` unconditionally.
                    534: 
                    535:    Default: `yes`
                    536: 
1.2     ! jdf       537:  * *MKTTINTERP* -- Can be set to `yes` or `no`. For X builds, decides if the
        !           538:    TrueType bytecode interpreter is turned on. See
1.1       jdf       539:    [freetype.org](http://freetype.org/patents.html) for details.
                    540: 
                    541:    Default: `no`
                    542: 
1.2     ! jdf       543:  * *MKUNPRIVED* -- Can be set to `yes` or `no`. Indicates whether an
        !           544:    unprivileged install will occur. The user, group, permissions and file flags
        !           545:    will not be set on the installed items; instead the information will be
        !           546:    appended to a file called `METALOG` in `DESTDIR`. The contents of `METALOG`
        !           547:    are used during the generation of the distribution tar files to ensure that
1.1       jdf       548:    the appropriate file ownership is stored.
                    549: 
                    550:    Default:  `no`
                    551: 
1.2     ! jdf       552:  * *MKUPDATE* -- Can be set to `yes` or `no`. Indicates whether all install
        !           553:    operations intended to write to `DESTDIR` will compare file timestamps before
        !           554:    installing, and skip the install phase if the destination files are
1.1       jdf       555:    up-to-date. This also has implications on full builds (See below).
                    556: 
                    557:    Default: `no`
                    558: 
1.2     ! jdf       559:  * *MKX11* -- Can be set to `yes` or `no`. Indicates whether X11R6 is built from
1.1       jdf       560:    `X11SRCDIR`.
                    561: 
                    562:    Default: `yes`
                    563: 
1.2     ! jdf       564:  * *TOOLDIR* -- Directory to hold the host tools, once built. This directory
        !           565:    should be unique to a given host system and NetBSD source tree. (However,
        !           566:    multiple targets may share the same `TOOLDIR`; the target-dependent files
        !           567:    have unique names). If unset, a default based on the
        !           568:    [uname(1)](http://netbsd.gw.com/cgi-bin/man-cgi?uname+1+NetBSD-5.0.1+i386)
1.1       jdf       569:    information of the host platform will be created in the `.OBJDIR` of `src`.
                    570: 
                    571:    Default: Unset.
                    572: 
1.2     ! jdf       573:  * *USETOOLS* -- Indicates whether the tools specified by `TOOLDIR` should be
1.1       jdf       574:    used as part of a build in progress. Must be set to `yes` if cross-compiling.
                    575: 
                    576:     * `yes` -- Use the tools from `TOOLDIR`.
1.2     ! jdf       577:        * `no` -- Do not use the tools from `TOOLNAME`, but refuse to build native
1.1       jdf       578:          compilation tool components that are version-specific for that tool.
1.2     ! jdf       579:        * `never` -- Do not use the tools from `TOOLNAME`, even when building native
        !           580:          tool components. This is similar to the traditional NetBSD build method,
        !           581:          but does not verify that the compilation tools in use are up-to-date
        !           582:          enough in order to build the tree successfully. This may cause build or
1.1       jdf       583:          runtime problems when building the whole NetBSD source tree.
                    584: 
1.2     ! jdf       585:    Default: `yes` if building all or part of a whole NetBSD source tree
        !           586:    (detected automatically); `no` otherwise (to preserve traditional semantics
        !           587:    of the `bsd.*.mk`
        !           588:    [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-5.0.1+i386)
1.1       jdf       589:    include files).
                    590: 
1.2     ! jdf       591:  * *X11SRCDIR* -- Directory containing the X11R6 source. The main X11R6 source
1.1       jdf       592:    is found in `X11SRCDIR/xfree/xc`.
                    593: 
                    594:    Default: `usr/xsrc`
                    595: 
1.2     ! jdf       596: The following variables only affect the top level `Makefile` and do not affect
1.1       jdf       597: manually building subtrees of the NetBSD source code.
                    598: 
1.2     ! jdf       599:  * *INSTALLWORLDDIR* -- Location for the `make installworld` target to install
1.1       jdf       600:    to.
                    601: 
                    602:    Default: `/`
                    603: 
1.2     ! jdf       604:  * *MKOBJDIRS* -- Can be set to `yes` or `no`. Indicates whether object
        !           605:    directories will be created automatically (via a `make obj` pass) at the
1.1       jdf       606:    start of a build.
                    607: 
                    608:    Default: `no`
                    609: 
1.2     ! jdf       610:  * *MKUPDATE* -- Can be set to `yes` or `no`. If set, then addition to the
        !           611:    effects described for `MKUPDATE=yes` above, this implies the effect of
1.1       jdf       612:    `NOCLEANDIR` (i.e., `make cleandir` is avoided).
                    613: 
                    614:    Default: `no`
                    615: 
1.2     ! jdf       616:  * *NOCLEANDIR* -- If set, avoids the `make cleandir` phase of a full build.
        !           617:    This has the effect of allowing only changed files in a source tree to
        !           618:    recompiled. This can speed up builds when updating only a few files in the
1.1       jdf       619:    tree.
                    620: 
                    621:    Default: Unset
                    622: 
1.2     ! jdf       623:  * *NODISTRIBDIRS* -- If set, avoids the `make distrib-dirs` of a full build.
        !           624:    This skips running
        !           625:    [mtree(8)](http://netbsd.gw.com/cgi-bin/man-cgi?mtree+8+NetBSD-5.0.1+i386) on
        !           626:    `DESTDIR`, useful on systems where building as an unprivileged user, or where
1.1       jdf       627:    it is known that the system wide mtree files have not changed.
                    628: 
                    629:    Default: Unset
                    630: 
1.2     ! jdf       631:  * *NOINCLUDES* -- If set, avoids the `make includes` phase of a full build.
        !           632:    This has the effect of preventing
        !           633:    [make(1)](http://netbsd.gw.com/cgi-bin/man-cgi?make+1+NetBSD-5.0.1+i386) from
        !           634:    thinking that some programs are out-of-date simply because system include
        !           635:    files have changed. However, this option should not be trusted when updating
        !           636:    the entire NetBSD source tree arbitrarily; it is suggested to use
1.1       jdf       637:    `MKUPDATE=yes` in that case.
                    638: 
                    639:    Default: Unset
                    640: 
1.2     ! jdf       641:  * *RELEASEDIR* -- If set, specifies the directory to which a
        !           642:    [release(7)](http://netbsd.gw.com/cgi-bin/man-cgi?release+7+NetBSD-5.0.1+i386)
1.1       jdf       643:    layout will be written at the end of a `make release`.
                    644: 
                    645:    Default: Unset
                    646: 
1.2     ! jdf       647:  * *TOOLCHAIN\_MISSING* -- Set to `yes` on platforms for which there is no
        !           648:    working in-tree toolchain, or if you need/wish using native system toolchain
1.1       jdf       649:    (i.e. non-cross tools available via your shell search path).
                    650: 
                    651:    Default: depends on target platform; on platforms with in-tree toolchain is set to `no`.
                    652: 

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