xref: /netbsd-src/share/mk/bsd.README (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1#	$NetBSD: bsd.README,v 1.64 2000/06/23 06:11:05 thorpej Exp $
2#	@(#)bsd.README	8.2 (Berkeley) 4/2/94
3
4This is the README file for the new make "include" files for the BSD
5source tree.  The files are installed in /usr/share/mk, and are, by
6convention, named with the suffix ".mk".
7
8Note, this file is not intended to replace reading through the .mk
9files for anything tricky.
10
11=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
12
13RANDOM THINGS WORTH KNOWING:
14
15The files are simply C-style #include files, and pretty much behave like
16you'd expect.  The syntax is slightly different in that a single '.' is
17used instead of the hash mark, i.e. ".include <bsd.prog.mk>".
18
19One difference that will save you lots of debugging time is that inclusion
20of the file is normally done at the *end* of the Makefile.  The reason for
21this is because .mk files often modify variables and behavior based on the
22values of variables set in the Makefile.  To make this work, remember that
23the FIRST target found is the target that is used, i.e. if the Makefile has:
24
25	a:
26		echo a
27	a:
28		echo a number two
29
30the command "make a" will echo "a".  To make things confusing, the SECOND
31variable assignment is the overriding one, i.e. if the Makefile has:
32
33	a=	foo
34	a=	bar
35
36	b:
37		echo ${a}
38
39the command "make b" will echo "bar".  This is for compatibility with the
40way the V7 make behaved.
41
42It's fairly difficult to make the BSD .mk files work when you're building
43multiple programs in a single directory.  It's a lot easier split up the
44programs than to deal with the problem.  Most of the agony comes from making
45the "obj" directory stuff work right, not because we switched to a new version
46of make.  So, don't get mad at us, figure out a better way to handle multiple
47architectures so we can quit using the symbolic link stuff.  (Imake doesn't
48count.)
49
50The file .depend in the source directory is expected to contain dependencies
51for the source files.  This file is read automatically by make after reading
52the Makefile.
53
54The variable DESTDIR works as before.  It's not set anywhere but will change
55the tree where the file gets installed.
56
57The profiled libraries are no longer built in a different directory than
58the regular libraries.  A new suffix, ".po", is used to denote a profiled
59object, and ".so" denotes a shared (position-independent) object.
60
61The following variables that control how things are made/installed that
62are not set by default. These should not be set by Makefiles; they're for
63the user to define in MAKECONF (see bsd.own.mk, below) or on the make(1)
64command line:
65
66BUILD 		If defined, 'make install' checks that the targets in the
67		source directories are up-to-date and remakes them if they
68                are out of date, instead of blindly trying to install
69                out of date or non-existant targets.
70
71UPDATE 		If defined, 'make install' only installs targets that are
72		more recently modified in the source directories that their
73		installed counterparts.
74
75UNPRIVILEGED	If defined, don't set the owner/group/mode when installing
76		files or directories.  This allows a non-root "make install".
77
78MKCATPAGES	If "no", don't build or install the catman pages.
79
80MKDOC		If "no", don't build or install the documentation.
81
82MKINFO		If "no", don't build or install Info documentation from
83		Texinfo source files.
84
85MKLINT		If "no", don't build or install the lint libraries.
86
87MKMAN		If "no", don't build or install the man or catman pages.
88		Also acts as "MKCATPAGES=no"
89
90MKNLS		If "no", don't build or install the NLS files.
91
92MKOBJ		If "no", don't enable the rule which creates objdirs.
93		"yes" by default.
94
95MKOBJDIRS	If "no", don't create objdirs during a "make build".
96		"no" by default.
97
98MKPIC		If "no", don't build or install shared libraries.
99
100MKPICINSTALL	If "no", don't install the *_pic.a libraries.
101
102MKPROFILE	If "no", don't build or install the profiling libraries.
103
104MKSHARE		If "no", act as "MKCATPAGES=no MKDOC=no MKINFO=no MKMAN=no
105		MKNLS=no".  I.e, don't build catman pages, documentation,
106		Info documentation, man pages, NLS files, ...
107
108=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
109
110The include file <sys.mk> has the default rules for all makes, in the BSD
111environment or otherwise.  You probably don't want to touch this file.
112
113=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
114
115The include file <bsd.man.mk> handles installing manual pages and their
116links.
117
118It has a two targets:
119
120	maninstall:
121		Install the manual page sources and their links.
122	catinstall:
123		Install the preformatted manual pages and their links.
124
125It sets/uses the following variables:
126
127MANDIR		Base path for manual installation.
128
129MANGRP		Manual group.
130
131MANOWN		Manual owner.
132
133MANMODE		Manual mode.
134
135MANSUBDIR	Subdirectory under the manual page section, i.e. "/vax"
136		or "/tahoe" for machine specific manual pages.
137
138MAN		The manual pages to be installed (use a .1 - .9 suffix).
139
140MLINKS		List of manual page links (using a .1 - .9 suffix).  The
141		linked-to file must come first, the linked file second,
142		and there may be multiple pairs.  The files are soft-linked.
143
144The include file <bsd.man.mk> includes a file named "../Makefile.inc" if
145it exists.
146
147=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
148
149The include file <bsd.own.mk> contains source tree configuration parameters,
150such as the owners, groups, etc. for both manual pages and binaries, and
151a few global "feature configuration" parameters.
152
153It has no targets.
154
155To get system-specific configuration parameters, bsd.own.mk will try to
156include the file specified by the "MAKECONF" variable.  If MAKECONF is not
157set, or no such file exists, the system make configuration file, /etc/mk.conf
158is included.  These files may define any of the variables described below.
159
160bsd.own.mk sets the following variables, if they are not already defined
161(defaults are in brackets):
162
163BSDSRCDIR	The real path to the system sources, so that 'make obj'
164		will work correctly. [/usr/src]
165
166BSDOBJDIR	The real path to the system 'obj' tree, so that 'make obj'
167		will work correctly. [/usr/obj]
168
169BINGRP		Binary group. [wheel]
170
171BINOWN		Binary owner. [root]
172
173BINMODE		Binary mode. [555]
174
175NONBINMODE	Mode for non-executable files. [444]
176
177MANDIR		Base path for manual installation. [/usr/share/man/cat]
178
179MANGRP		Manual group. [wheel]
180
181MANOWN		Manual owner. [root]
182
183MANMODE		Manual mode. [${NONBINMODE}]
184
185MANINSTALL	Manual installation type: maninstall, catinstall, or both
186
187LIBDIR		Base path for library installation. [/usr/lib]
188
189LINTLIBDIR	Base path for lint(1) library installation. [/usr/libdata/lint]
190
191LIBGRP		Library group. [${BINGRP}]
192
193LIBOWN		Library owner. [${BINOWN}]
194
195LIBMODE		Library mode. [${NONBINMODE}]
196
197DOCDIR		Base path for system documentation (e.g. PSD, USD, etc.)
198	        installation. [/usr/share/doc]
199
200HTMLDOCDIR	Base path for html system documentation installation.
201		[/usr/share/doc/html]
202
203DOCGRP		Documentation group. [wheel]
204
205DOCOWN		Documentation owner. [root]
206
207DOCMODE		Documentation mode. [${NONBINMODE}]
208
209NLSDIR		Base path for National Language Support files installation.
210		[/usr/share/nls]
211
212NLSGRP		National Language Support files group. [wheel]
213
214NLSOWN		National Language Support files owner. [root]
215
216NLSMODE		National Language Support files mode. [${NONBINMODE}]
217
218STRIPFLAG	The flag passed to the install program to cause the binary
219		to be stripped.  This is to be used when building your
220		own install script so that the entire system can be made
221		stripped/not-stripped using a single knob. [-s]
222
223COPY		The flag passed to the install program to cause the binary
224		to be copied rather than moved.  This is to be used when
225		building our own install script so that the entire system
226		can either be installed with copies, or with moves using
227		a single knob. [-c]
228
229Additionally, the following variables may be set by bsd.own.mk or in a
230make configuration file to modify the behaviour of the system build
231process (default values are in brackets along with comments, if set by
232bsd.own.mk):
233
234MKCRYPTO	If set to "no", no cryptography support will be built
235		into the system.  Defaults to "yes".
236
237NOCRYPTO	If set, it is equivalent to setting MKCRYPTO to "no".
238
239MKCRYPTO_RSA	If set to "no", RSA support will not be built into
240		the system's cryptography libraries.  This implies
241		that SSLv2 support will not be present.  Defaults to "yes".
242
243NOCRYPTO_RSA	If set, it is equivalent to setting MKCRYPTO_RSA to "no".
244
245MKCRYPTO_IDEA	If set to "no", IDEA support will not be built into
246		the system's cryptography libraries.  Defaults to "yes".
247
248NOCRYPTO_IDEA	If set, it is equivalent to setting MKCRYPTO_IDEA to "no".
249
250MKCRYPTO_RC5	If set to "no", RC5 support will not be built into
251		the system's cryptography libraries.  Defaults to "yes".
252
253NOCRYPTO_RC5	If set, it is equivalent to setting MKCRYPTO_RC5 to "no".
254
255MKKERBEROS	If set to "no", disables building Kerberos (v4 or v5)
256		support into various system utilities that support it.
257		Defaults to "yes".  NOTE: This does not affect the
258		building of the Kerberos libraries or infrastructure
259		programs themselves.  To completely disable Kerberos,
260		set MKCRYPTO to "no".
261
262NOKERBEROS	If set, it is equivalent to setting MKKERBEROS to "no".
263
264SKEY		Compile in support for S/key authentication. [yes, set
265		unconditionally]
266
267MANZ		Compress manual pages at installation time.
268
269SYS_INCLUDE	Copy or symlink kernel include files into /usr/include.
270		Possible values are "symlinks" or "copies" (which is
271		the same as the variable being unset).
272
273NOPROFILE	Do not build profiled versions of system libraries
274
275NOPIC		Do not build PIC versions of system libraries, and
276		do not build shared libraries.  [set if ${MACHINE_ARCH}
277		is "sparc64", unset otherwise.]
278
279NOLINT		Do not build lint libraries.
280
281OBJECT_FMT	Object file format. [set to "ELF" on architectures that
282		use ELF -- currently if ${MACHINE_ARCH} is "alpha",
283		"mipsel", "mipseb", "powerpc", "sparc", "sparc64",
284		and "i386", or set to "a.out" on other architectures].
285
286
287bsd.own.mk is generally useful when building your own Makefiles so that
288they use the same default owners etc. as the rest of the tree.
289
290=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
291
292The include file <bsd.prog.mk> handles building programs from one or
293more source files, along with their manual pages.  It has a limited number
294of suffixes, consistent with the current needs of the BSD tree.
295
296It has eight targets:
297
298	all:
299		build the program and its manual page
300	clean:
301		remove the program, any object files and the files a.out,
302		Errs, errs, mklog, and ${PROG}.core.
303	cleandir:
304		remove all of the files removed by the target clean, as
305		well as .depend, tags, and any manual pages.
306		`distclean' is a synonym for `cleandir'.
307	depend:
308		make the dependencies for the source files, and store
309		them in the file .depend.
310	includes:
311		install any header files.
312	install:
313		install the program and its manual pages; if the Makefile
314		does not itself define the target install, the targets
315		beforeinstall and afterinstall may also be used to cause
316		actions immediately before and after the install target
317		is executed.
318	lint:
319		run lint on the source files
320	tags:
321		create a tags file for the source files.
322
323It sets/uses the following variables:
324
325BINGRP		Binary group.
326
327BINOWN		Binary owner.
328
329BINMODE		Binary mode.
330
331CLEANFILES	Additional files to remove for the clean and cleandir targets.
332
333COPTS		Additional flags to the compiler when creating C objects.
334
335CPPFLAGS	Additional flags to the C pre-processor
336
337LDADD		Additional loader objects.  Usually used for libraries.
338		For example, to load with the compatibility and utility
339		libraries, use:
340
341			LDADD+=-lutil -lcompat
342
343LDFLAGS		Additional loader flags.
344
345LINKS		The list of binary links; should be full pathnames, the
346		linked-to file coming first, followed by the linked
347		file.  The files are hard-linked.  For example, to link
348		/bin/test and /bin/[, use:
349
350			LINKS=	${DESTDIR}/bin/test ${DESTDIR}/bin/[
351
352SYMLINKS	The list of symbolic links; should be full pathnames.
353                Syntax is identical to LINKS. Note that DESTDIR is not
354		automatically included in the link.
355
356MAN		Manual pages (should end in .1 - .9).  If no MAN variable is
357		defined, "MAN=${PROG}.1" is assumed.
358
359PROG		The name of the program to build.  If not supplied, nothing
360		is built.
361
362PROGNAME	The name that the above program will be installed as, if
363		different from ${PROG}.
364
365SRCS		List of source files to build the program.  If SRCS is not
366		defined, it's assumed to be ${PROG}.c.
367
368DPADD		Additional dependencies for the program.  Usually used for
369		libraries.  For example, to depend on the compatibility and
370		utility libraries use:
371
372			DPADD+=${LIBCOMPAT} ${LIBUTIL}
373
374		The following libraries are predefined for DPADD:
375
376		LIBCRT0?=	${DESTDIR}/usr/lib/crt0.o
377		LIBC?=		${DESTDIR}/usr/lib/libc.a
378		LIBC_PIC?=	${DESTDIR}/usr/lib/libc_pic.a
379		LIBCOMPAT?=	${DESTDIR}/usr/lib/libcompat.a
380		LIBCRYPT?=	${DESTDIR}/usr/lib/libcrypt.a
381		LIBCURSES?=	${DESTDIR}/usr/lib/libcurses.a
382		LIBDBM?=	${DESTDIR}/usr/lib/libdbm.a
383		LIBDES?=	${DESTDIR}/usr/lib/libdes.a
384		LIBEDIT?=	${DESTDIR}/usr/lib/libedit.a
385		LIBGCC?=	${DESTDIR}/usr/lib/libgcc.a
386		LIBGNUMALLOC?=	${DESTDIR}/usr/lib/libgnumalloc.a
387		LIBIPSEC?=	${DESTDIR}/usr/lib/libipsec.a
388		LIBKDB?=	${DESTDIR}/usr/lib/libkdb.a
389		LIBKRB?=	${DESTDIR}/usr/lib/libkrb.a
390		LIBKVM?=	${DESTDIR}/usr/lib/libkvm.a
391		LIBL?=		${DESTDIR}/usr/lib/libl.a
392		LIBM?=		${DESTDIR}/usr/lib/libm.a
393		LIBMENU?=	${DESTDIR}/usr/lib/libmenu.a
394		LIBMP?=		${DESTDIR}/usr/lib/libmp.a
395		LIBNTP?=	${DESTDIR}/usr/lib/libntp.a
396		LIBPC?=		${DESTDIR}/usr/lib/libpc.a
397		LIBPCAP?=	${DESTDIR}/usr/lib/libpcap.a
398		LIBPLOT?=	${DESTDIR}/usr/lib/libplot.a
399		LIBPOSIX?=	${DESTDIR}/usr/lib/libposix.a
400		LIBRESOLV?=	${DESTDIR}/usr/lib/libresolv.a
401		LIBRPCSVC?=	${DESTDIR}/usr/lib/librpcsvc.a
402		LIBSKEY?=	${DESTDIR}/usr/lib/libskey.a
403		LIBTERMCAP?=	${DESTDIR}/usr/lib/libtermcap.a
404		LIBTELNET?=	${DESTDIR}/usr/lib/libtelnet.a
405		LIBUTIL?=	${DESTDIR}/usr/lib/libutil.a
406		LIBWRAP?=	${DESTDIR}/usr/lib/libwrap.a
407		LIBY?=		${DESTDIR}/usr/lib/liby.a
408		LIBZ?=		${DESTDIR}/usr/lib/libz.a
409
410
411SHAREDSTRINGS	If defined, a new .c.o rule is used that results in shared
412		strings, using xstr(1). Note that this will not work with
413		parallel makes.
414
415STRIPFLAG	The flag passed to the install program to cause the binary
416		to be stripped.
417
418SUBDIR		A list of subdirectories that should be built as well.
419		Each of the targets will execute the same target in the
420		subdirectories.
421
422SCRIPTS		A list of interpreter scripts [file.{sh,csh,pl,awk,...}].
423		These are installed exactly like programs.
424
425SCRIPTSNAME	The name that the above program will be installed as, if
426		different from ${SCRIPTS}. These can be further specialized
427		by setting SCRIPTSNAME_<script>.
428
429FILES		A list of files to install. The installation is controlled
430		by the FILESNAME, FILESOWN, FILESGRP, FILESMODE, FILESDIR
431		variables that can be further specialized by FILES<VAR>_<file>
432
433The include file <bsd.prog.mk> includes the file named "../Makefile.inc"
434if it exists, as well as the include file <bsd.man.mk>.
435
436Some simple examples:
437
438To build foo from foo.c with a manual page foo.1, use:
439
440	PROG=	foo
441
442	.include <bsd.prog.mk>
443
444To build foo from foo.c with a manual page foo.2, add the line:
445
446	MAN=	foo.2
447
448If foo does not have a manual page at all, add the line:
449
450	NOMAN=	noman
451
452If foo has multiple source files, add the line:
453
454	SRCS=	a.c b.c c.c d.c
455
456=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
457
458The include file <bsd.subdir.mk> contains the default targets for building
459subdirectories.  It has the same eight targets as <bsd.prog.mk>: all,
460clean, cleandir, depend, includes, install, lint, and tags.  For all of
461the directories listed in the variable SUBDIRS, the specified directory
462will be visited and the target made.  There is also a default target which
463allows the command "make subdir" where subdir is any directory listed in
464the variable SUBDIRS.
465
466=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
467
468The include file <bsd.links.mk> handles the LINKS and SYMLINKS variables
469and is included from from bsd.lib.mk and bsd.prog.mk.
470
471=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
472
473The include file <bsd.files.mk> handles the FILES variables and is included
474from bsd.lib.mk and bsd.prog.mk.
475
476=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
477
478The include file <bsd.inc.mk> defines the includes target and uses two
479variables:
480
481INCS	The list of include files
482
483INCSDIR	The location to install the include files.
484
485=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
486
487The include file <bsd.kinc.mk> defines the many targets (includes,
488subdirectories, etc.), and is used by kernel makefiles to handle
489include file installation.  It is intended to be included alone, by
490kernel Makefiles.  Please see bsd.kinc.mk for more details, and keep
491the documentation in that file up to date.
492
493=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
494
495The include file <bsd.info.mk> is used to generate and install GNU Info
496documentation from respective Texinfo source files.  It defines three
497implicit targets (.txi.info, .texi.info, and .texinfo.info), and uses the
498following variables:
499
500TEXINFO		List of Texinfo source files.  Info documentation will
501		consist of single files with the extension replaced by
502		.info.
503
504INFOFLAGS	Flags to pass to makeinfo.  []
505
506INSTALL_INFO	Name of install-info program.  [install-info]
507
508MAKEINFO	Name of makeinfo program.  [makeinfo]
509
510=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
511
512The include file <bsd.sys.mk> is used by <bsd.prog.mk> and
513<bsd.lib.mk>.  It contains overrides that are used when building
514the NetBSD source tree.  For instance, if "PARALLEL" is defined by
515the program/library Makefile, it includes a set of rules for lex and
516yacc that allow multiple lex and yacc targets to be built in parallel.
517
518=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
519
520The include file <bsd.lib.mk> has support for building libraries.  It has
521the same eight targets as <bsd.prog.mk>: all, clean, cleandir, depend,
522includes, install, lint, and tags.  Additionally, it has a checkver target
523which checks for installed shared object libraries whose version is greater
524that the version of the source. It has a limited number of suffixes,
525consistent with the current needs of the BSD tree.
526
527It sets/uses the following variables:
528
529LIB		The name of the library to build.
530
531LIBDIR		Target directory for libraries.
532
533LINTLIBDIR	Target directory for lint libraries.
534
535LIBGRP		Library group.
536
537LIBOWN		Library owner.
538
539LIBMODE		Library mode.
540
541LDADD		Additional loader objects.
542
543MAN		The manual pages to be installed (use a .1 - .9 suffix).
544
545MKLINKLIB	If "no", act as "MKPICINSTALL=no MKPROFILE=no".
546		Also:
547			- don't install the .a libraries
548			- don't install _pic.a libraries on PIC systems
549			- don't build .a libraries on PIC systems
550			- don't install the .so symlink on ELF systems
551		I.e, only install the shared library (and the .so.major
552		symlink on ELF).
553
554MKPICLIB	If "no", don't build _pic.a libraries, and build the
555		shared object libraries from the .a libraries.  A
556		symlink is installed in ${DESTDIR}/usr/lib for the
557		_pic.a library pointing to the .a library.
558
559NOCHECKVER_<library>
560NOCHECKVER	If set, disables checking for installed shared object
561		libraries with versions greater than the source.  A
562		particular library name, without the "lib" prefix, may
563		be appended to the variable name to disable the check for
564		only that library.
565
566SRCS		List of source files to build the library.  Suffix types
567		.s, .c, and .f are supported.  Note, .s files are preferred
568		to .c files of the same name.  (This is not the default for
569		versions of make.)
570
571The include file <bsd.lib.mk> includes the file named "../Makefile.inc"
572if it exists, as well as the include file <bsd.man.mk>.
573
574It has rules for building profiled objects; profiled libraries are
575built by default.
576
577Libraries are ranlib'd when made.
578
579=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
580
581The include file <bsd.obj.mk> defines targets related to the creation
582and use of separated object and source directories.
583
584If an environment variable named MAKEOBJDIRPREFIX is set, make(1) uses
585${MAKEOBJDIRPREFIX}${.CURDIR} as the name of the object directory if
586it exists.  Otherwise make(1) looks for the existance of a
587subdirectory (or a symlink to a directory) of the source directory
588into which built targets should be placed.  If an environment variable
589named MAKEOBJDIR is set, make(1) uses its value as the name of the
590object directory; failing that, make first looks for a subdirectory
591named "obj.${MACHINE}", and if that doesn't exist, it looks for "obj".
592
593Object directories are not created automatically by make(1) if they
594don't exist; you need to run a separate "make obj".  (This will happen
595during a top-level build if "MKOBJDIRS" is set to a value other than
596"no").  When the source directory is a subdirectory of ${BSDSRCDIR} --
597and this is determined by a simple string prefix comparison -- object
598directories are created in a separate object directory tree, and a
599symlink to the object directory in that tree is created in the source
600directory; otherwise, "make obj" assumes that you're not in the main
601source tree and that it's not safe to use a separate object tree.
602
603Several variables used by <bsd.obj.mk> control exactly what
604directories and links get created during a "make obj":
605
606MAKEOBJDIR	If set, this is the component name of the object
607		directory.
608
609OBJMACHINE	If this is set but MAKEOBJDIR is not set, creates
610		object directories or links named "obj.${MACHINE}";
611		otherwise, just creates ones named "obj".
612
613USR_OBJMACHINE  If set, and the current directory is a subdirectory of
614		${BSDSRCDIR}, create object directory in the
615		corresponding subdirectory of ${BSDOBJDIR}.${MACHINE};
616		otherwise, create it in the corresponding subdirectory
617		of ${BSDOBJDIR}
618
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620
621The include file <bsd.kernobj.mk> defines variables related to the
622location of kernel sources and object directories.
623
624KERNSRCDIR	Is the location of the top of the kernel src.
625		It defaults to ${BSDSRCDIR}/sys, but the top-level
626		Makefile.inc sets it to ${ABSTOP}/sys (ABSTOP is the
627		absolute path to the directory where the top-level
628		Makefile.inc was found.
629
630KERNARCHDIR	Is the location of the machine dependent kernel
631		sources.  It defaults to arch/${MACHINE}
632
633KERNCONFDIR	Is where the configuration files for kernels are
634		found; default is ${KERNSRCDIR}/${KERNARCHDIR}/conf.
635
636KERNOBJDIR	Is the kernel build directory.  The kernel GENERIC for
637		instance will be compiled in ${KERNOBJDIR}/GENERIC.
638		The default value is
639		${MAKEOBJDIRPREFIX}${KERNSRCDIR}/${KERNARCHDIR}/compile
640		if it exists or the target 'obj' is being made.
641		Otherwise the default is
642		${KERNSRCDIR}/${KERNARCHDIR}/compile.
643
644It is important that Makefiles (such as those under src/distrib) that
645wish to find compiled kernels use bsd.kernobj.mk and ${KERNOBJDIR}
646rather than make assumptions about the location of the compiled kernel.
647
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649