This is the README file for the "include" files for the FreeBSD
source tree.  The files are installed in /usr/share/mk, and are by
convention, named with the suffix ".mk".  These files store several
build options and should be handled with caution.

Note, this file is not intended to replace reading through the .mk
files for anything tricky.

There are two main types of make include files.  One type is the generally
usable make include files, such as bsd.prog.mk and bsd.lib.mk.  The other is
the internal make include files, such as bsd.files.mk and bsd.man.mk, which
can not/should not be used directly but are used by the other make include
files.  In most cases it is only interesting to include bsd.prog.mk or
bsd.lib.mk.

bsd.arch.inc.mk		- includes arch-specific Makefile.$arch
bsd.compat.mk		- definitions for building programs against compat ABIs
bsd.compiler.mk		- defined based on current compiler
bsd.confs.mk		- install of configuration files
bsd.cpu.mk		- sets CPU/arch-related variables (included from sys.mk)
bsd.crunchgen.mk	- building crunched binaries using crunchgen(1)
bsd.dep.mk		- handle Makefile dependencies
bsd.dirs.mk		- handle directory creation
bsd.doc.mk		- building troff system documents
bsd.endian.mk		- TARGET_ENDIAN=1234(little) or 4321 (big) for target
bsd.files.mk		- install of general purpose files
bsd.incs.mk		- install of include files
bsd.info.mk		- building GNU Info hypertext system (deprecated)
bsd.init.mk		- initialization for the make include files
bsd.kmod.mk		- building loadable kernel modules
bsd.lib.mk		- support for building libraries
bsd.libnames.mk		- define library names
bsd.links.mk		- install of links (sym/hard)
bsd.man.mk		- install of manual pages and their links
bsd.nls.mk		- build and install of NLS catalogs
bsd.obj.mk		- creating 'obj' directories and cleaning up
bsd.own.mk		- define common variables
bsd.port.mk		- building ports
bsd.port.post.mk	- building ports
bsd.port.pre.mk		- building ports
bsd.port.subdir.mk	- targets for building subdirectories for ports
bsd.prog.mk		- building programs from source files
bsd.progs.mk		- build multiple programs from sources
bsd.snmpmod.mk		- building modules for the SNMP daemon bsnmpd
bsd.subdir.mk		- targets for building subdirectories
bsd.sys.mk		- common settings used for building FreeBSD sources
bsd.test.mk		- building test programs from source files
sys.mk			- default rules for all makes

This file does not document bsd.port*.mk.  They are documented in ports(7).

See also make(1), mkdep(1), style.Makefile(5) and `PMake - A
Tutorial', located in /usr/share/doc/psd/12.make.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

Random things worth knowing about this document:

If appropriate when documenting the variables the default value is
indicated using square brackets e.g. [gzip].
In some cases the default value depend on other values (e.g. system
architecture).  In these cases the most common value is indicated.

This document contains some simple examples of the usage of the BSD make
include files.  For more examples look at the makefiles in the FreeBSD
source tree.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

RANDOM THINGS WORTH KNOWING:

The files are like C-style #include files, and pretty much behave like
you'd expect.  The syntax is slightly different in that a single '.' is
used instead of the hash mark, i.e. ".include <bsd.prog.mk>".

One difference that will save you lots of debugging time is that inclusion
of the file is normally done at the *end* of the Makefile.  The reason for
this is because .mk files often modify variables and behavior based on the
values of variables set in the Makefile.  To make this work, remember that
the FIRST target found is the target that is used, i.e. if the Makefile has:

	a:
		echo a
	a:
		echo a number two

the command "make a" will echo "a".  To make things confusing, the SECOND
variable assignment is the overriding one, i.e. if the Makefile has:

	a=	foo
	a=	bar

	b:
		echo ${a}

the command "make b" will echo "bar".  This is for compatibility with the
way the V7 make behaved.

It's fairly difficult to make the BSD .mk files work when you're building
multiple programs in a single directory.  It's a lot easier to split up
the programs than to deal with the problem.  Most of the agony comes from
making the "obj" directory stuff work right, not because we switch to a new
version of make.  So, don't get mad at us, figure out a better way to handle
multiple architectures so we can quit using the symbolic link stuff.
(Imake doesn't count.)

The file .depend in the source directory is expected to contain dependencies
for the source files.  This file is read automatically by make after reading
the Makefile.

The variable DESTDIR works as before.  It's not set anywhere but will change
the tree where the file gets installed.

A ".pico" suffix denotes a position-independent relocatable object.
".nossppico" denotes a position-independent relocatable object without
stack smashing protection and without sanitizer instrumentation.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The following variables are common:

ACFLAGS		Flags to the compiler when preprocessing and
		assembling .S files.
ACFLAGS.${SRC}
		Flags dependent on source file name.
ACFLAGS.${.TARGET:T}
		Flags dependent on output file name.

AFLAGS		Flags to the assembler when assembling .s files.
AFLAGS.${SRC}
		Flags dependent on source file name.
AFLAGS.${.TARGET:T}
		Flags dependent on output file name.

CFLAGS		Flags to the compiler when creating C objects.
CFLAGS.${SRC}
		Flags dependent on source file name.
CFLAGS.${.TARGET:T}
		Flags dependent on output file name.
CFLAGS.${COMPILER_TYPE}
		Flags dependent on compiler added to CFLAGS.
CFLAGS.${MACHINE_ARCH}
		Architectural flags added to CFLAGS.
CFLAGS_NO_SIMD	Add this to CFLAGS for programs that don't want any SIMD
		instructions generated. It is setup in bsd.cpu.mk to an
		appropriate value for the compiler and target.

CXXFLAGS.${COMPILER_TYPE}
		Flags dependent on compiler added to CXXFLAGS.
CXXFLAGS.${MACHINE_ARCH}
		Architectural flags added to CXXFLAGS.
CXXFLAGS.${SRC}
		Flags dependent on source file name.
CXXFLAGS.${.TARGET:T}
		Flags dependent on output file name.

DPADD		Additional dependencies.  Usually used for libraries.
		For example, to depend on the compatibility and utility
		libraries use:

			DPADD=${LIBCOMPAT} ${LIBUTIL}

		There is a predefined identifier for each (non-shared)
		library and object.  Library file names are
		transformed to identifiers by removing the extension and
		converting to upper case.

		There are no special identifiers for shared libraries
		or objects.  The identifiers for the standard
		libraries are used in DPADD.  This works correctly iff
		all the libraries are built at the same time.
		Unfortunately, it causes unnecessary relinks to shared
		libraries when only the static libraries have changed.
		Dependencies on shared libraries should be only on the
		library version numbers.

LDADD		Additional linker objects.  Usually used to add libraries.
		For example, to load with the compatibility and utility
		libraries, use:

			LDADD=-lutil -lcompat

LDADD.${.TARGET:T}
		Loader objects dependent on output file name.

LDFLAGS		Additional linker flags. Passed to the linker via CC,
		since that's used to link programs as well, so linker
		specific flags need to be prefixed with -Wl, to work.
LDFLAGS.${.TARGET:T}
		Flags dependent on output file name.

LIBADD		Additional libraries.  This is for base system libraries
		and is only valid inside of the FreeBSD tree.
		Use LIBADD=name instead of LDADD=-lname.

LIBADD.${.TARGET:T}
		Libraries dependent on output file name.

SHARED_CFLAGS	Additional compiler flags used when creating shared or
		position independent object files.

COMPILER_FEATURES
		A list of features that the compiler supports. Zero or
		more of:
			c++11	Supports full C++ 11 standard.

COMPILER_TYPE	Type of compiler, either clang or gcc, though other
		values are possible. Don't assume != clang == gcc.

COMPILER_VERSION
		A numeric constant equal to:
		     major * 10000 + minor * 100 + tiny
		for the compiler's self-reported version.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <sys.mk> has the default rules for all makes, in the BSD
environment or otherwise.  You probably don't want to touch this file.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.arch.inc.mk> includes other Makefiles for specific
architectures, if they exist. It will include the first of the following
files that it finds: Makefile.${MACHINE}, Makefile.${MACHINE_ARCH},
Makefile.${MACHINE_CPUARCH}

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.man.mk> handles installing manual pages and their
links.

It has three targets:

	all-man:
		build manual pages.
	maninstall:
		install the manual pages and their links.
	manlint:
		verify the validity of manual pages.

It sets/uses the following variables:

MAN		The manual pages to be installed (use a .1 - .9 suffix).

MANDIR		Base path for manual installation.

MANGRP		Manual group.

MANMODE		Manual mode.

MANOWN		Manual owner.

MANSUBDIR	Subdirectory under the manual page section, i.e. "/vax"
		or "/tahoe" for machine specific manual pages.

MLINKS		List of manual page links (using a .1 - .9 suffix).  The
		linked-to file must come first, the linked file second,
		and there may be multiple pairs.  The files are hard-linked.

The include file <bsd.man.mk> includes a file named "../Makefile.inc" if
it exists.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.own.mk> contains the owners, groups, etc. for both
manual pages and binaries.

It has no targets.

It sets/uses the following variables:

BINGRP		Binary group.

BINMODE		Binary mode.

BINOWN		Binary owner.

MANDIR		Base path for manual installation.

MANGRP		Manual group.

MANMODE		Manual mode.

MANOWN		Manual owner.

INSTALL_LINK	Command to install a hard link.

INSTALL_SYMLINK	Command to install a symbolic link.

INSTALL_RSYMLINK	Command to install a relative symbolic link.

LINKOWN		Owner of hard links created by INSTALL_LINK.

LINKGRP		Group of hard links created by INSTALL_LINK.

LINKMODE	Mode of hard links created by INSTALL_LINK.

SYMLINKOWN	Owner of hard links created by INSTALL_[R]SYMLINK.

SYMLINKGRP	Group of hard links created by INSTALL_[R]SYMLINK.

SYMLINKMODE	Mode of hard links created by INSTALL_[R]SYMLINK.

This file is generally useful when building your own Makefiles so that
they use the same default owners etc. as the rest of the tree.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.prog.mk> handles building programs from one or
more source files, along with their manual pages.  It has a limited number
of suffixes, consistent with the current needs of the BSD tree.

It has seven targets:

	all:
		build the program and its manual page
	clean:
		remove the program and any object files.
	cleandir:
		remove all of the files removed by the target clean, as
		well as .depend, tags, and any manual pages.
	depend:
		make the dependencies for the source files, and store
		them in the file .depend.
	install:
		install the program and its manual pages; if the Makefile
		does not itself define the target install, the targets
		beforeinstall and afterinstall may also be used to cause
		actions immediately before and after the install target
		is executed.
	tags:
		create a tags file for the source files.

It sets/uses the following variables:

BINGRP		Binary group.

BINMODE		Binary mode.

BINOWN		Binary owner.

CLEANDIRS	Additional files (CLEANFILES) and directories (CLEANDIRS) to
CLEANFILES	remove during clean and cleandir targets.  "rm -rf" and
		"rm -f" are used, respectively.

DIRS		A list of variables referring to directories.  For example:

			DIRS+=	FOO
			FOO=	/usr/share/foo

		Owner, Group, Mode and Flags are handled by FOO_OWN,
		FOO_GRP, FOO_MODE and FOO_FLAGS, respectively.

		This allows FILESDIR to be set to FOO, and the directory
		will be created before the files are installed and the
		dependencies will be set correctly.

FILES		A list of non-executable files.
		The installation is controlled by the FILESNAME, FILESOWN,
		FILESGRP, FILESMODE, FILESDIR variables that can be
		further specialized by FILES<VAR>_<file>.

LINKS		The list of binary links; should be full pathnames, the
		linked-to file coming first, followed by the linked
		file.  The files are hard-linked.  For example, to link
		/bin/test and /bin/[, use:

			LINKS=	/bin/test /bin/[

LINKOWN		Owner of links created with LINKS [${BINOWN}].

LINKGRP		Group of links created with LINKS [${BINGRP}].

LINKMODE	Mode of links created with LINKS [${BINMODE}].


MAN		Manual pages.  If no MAN variable is defined,
		"MAN=${PROG}.1" is assumed. See bsd.man.mk for more details.

PROG		The name of the program to build.  If not supplied, nothing
		is built.

PROGNAME	The name that the above program will be installed as, if
		different from ${PROG}.

PROG_CXX	If defined, the name of the program to build.  Also
		causes <bsd.prog.mk> to link the program with the
		standard C++ library.  PROG_CXX overrides the value
		of PROG if PROG is also set.

PROGS		When used with <bsd.progs.mk>, allow building multiple
PROGS_CXX	PROG and PROG_CXX in one Makefile.  To define
		individual variables for each program the VAR.prog
		syntax should be used.  For example:

		PROGS=		foo bar
		SRCS.foo=	foo_src.c
		LDADD.foo=	-lutil
		SRCS.bar=	bar_src.c

		The supported variables are:
		- BINDIR
		- BINGRP
		- BINMODE
		- BINOWN
		- CFLAGS
		- CXXFLAGS
		- DEBUG_FLAGS
		- DPADD
		- DPSRCS
		- INTERNALPROG (no installation)
		- LDADD
		- LDFLAGS
		- LIBADD
		- LINKS
		- MAN
		- MLINKS
		- MK_WERROR=no
		- PROGNAME
		- SRCS
		- STRIP
		- WARNS

SCRIPTS		A list of interpreter scripts [file.{sh,csh,pl,awk,...}].
		The installation is controlled by the SCRIPTSNAME, SCRIPTSOWN,
		SCRIPTSGRP, SCRIPTSMODE, SCRIPTSDIR variables that can be
		further specialized by SCRIPTS<VAR>_<script>.

SRCS		List of source files to build the program.  If SRCS is not
		defined, it's assumed to be ${PROG}.c or, if PROG_CXX is
		defined, ${PROG_CXX}.cc.

STRIP		The flag passed to the install program to cause the binary
		to be stripped.  This is to be used when building your
		own install script so that the entire system can be made
		stripped/not-stripped using a single nob.

SUBDIR		A list of subdirectories that should be built as well.
		Each of the targets will execute the same target in the
		subdirectories.

The include file <bsd.prog.mk> includes the file named "../Makefile.inc"
if it exists, as well as the include file <bsd.man.mk>.

Some simple examples:

To build foo from foo.c with a manual page foo.1, use:

	PROG=	foo

	.include <bsd.prog.mk>

To build foo from foo.c with a manual page foo.2, add the line:

	MAN=	foo.2

If foo does not have a manual page at all, add the line:

	MAN=

If foo has multiple source files, add the line:

	SRCS=	a.c b.c c.c d.c

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file, <bsd.compat.mk>, allows programs (built with
<bsd.prog.mk>) to be built for one the ABI(s) supported by the
top-level Makefile.libcompat.  It requires that <bsd.prog.mk> also be
included.

NEED_COMPAT	Build and link targeting a compatibility ABI or fail if it
		is not available.  Supported values are "32", "soft", and
		"any" being a wildcard.

WANT_COMPAT	Similar to NEED_COMPAT, but build with the base ABI if
		the specified ABI is not available.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file, <bsd.snmpmod.mk>, handles building MIB modules for bsnmpd
from one or more source files, along with their manual pages.  It has a
limited number of suffixes, consistent with the current needs of the BSD
tree.

bsd.snmpmod.mk leverages bsd.lib.mk for building MIB modules and
bsd.files.mk for installing MIB description and definition files.

It implements the following additional targets:

	smilint:
		execute smilint on the MIBs defined by BMIBS.

		The net-mgmt/libsmi package must be installed before
		executing this target. The net-mgmt/net-snmp package
		should be installed as well to reduce false positives
		from smilint.

It sets/uses the following variables:

BMIBS		The MIB definitions to install.

BMIBSDIR	The directory where the MIB definitions are installed.
		This defaults to `${SHAREDIR}/snmp/mibs`.

DEFS		The MIB description files to install.

DEFSDIR		The directory where MIB description files are installed.
		This defaults to `${SHAREDIR}/snmp/defs`.

EXTRAMIBDEFS	Extra MIB description files to use as input when
		generating ${MOD}_oid.h and ${MOD}_tree.[ch].

EXTRAMIBSYMS	Extra MIB definition files used only for extracting
		symbols.

		EXTRAMIBSYMS are useful when resolving inter-module
		dependencies and are useful with files containing only
		enum-definitions.

		See ${MOD}_oid.h for more details.

LOCALBASE	The package root where smilint and the net-snmp
		definitions can be found

MOD		The bsnmpd module name.

SMILINT		smilint binary to use with the smilint make target.

SMILINT_FLAGS	flags to pass to smilint.

SMIPATH		A colon-separated directory path where MIBs definitions
		can be found. See "SMIPATH" in smi_config for more
		details.

XSYM		MIB names to extract symbols for. See ${MOD}_oid.h for
		more details.

It generates the following files:

${MOD}_tree.c	A source file and header which programmatically describes
${MOD}_tree.h	the MIB (type, OID name, ACCESS attributes, etc).

		The files are generated via "gensnmptree -p".

		See gensnmptree(1) for more details.

${MOD}_oid.h	A header which programmatically describes the MIB root and
		MIB tables.

		The files are generated via "gensnmptree -e".

		See gensnmptree(1) for more details.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.subdir.mk> contains the default targets for building
subdirectories.  It has the same seven targets as <bsd.prog.mk>: all, clean,
cleandir, depend, install, and tags.  For all of the directories listed in the
variable SUBDIRS, the specified directory will be visited and the target made.
There is also a default target which allows the command "make subdir" where
subdir is any directory listed in the variable SUBDIRS.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.lib.mk> has support for building libraries.  It has the
same seven targets as <bsd.prog.mk>: all, clean, cleandir, depend, install, and
tags.  It has a limited number of suffixes, consistent with the current needs of
the BSD tree.

It sets/uses the following variables:

LIB		The name of the library to build.  Both a shared and static
		library will be built.  NO_PIC can be set to only build a
		static library.

LIBDIR		Target directory for libraries.

LIBGRP		Library group.

LIBMODE		Library mode.

LIBOWN		Library owner.

LIBRARIES_ONLY	Do not build or install files other than the library.

LIB_CXX		The name of the library to build. It also causes
		<bsd.lib.mk> to link the library with the
		standard C++ library.  LIB_CXX overrides the value
		of LIB if LIB is also set.  Both a shared and static library
		will be built.  NO_PIC can be set to only build a static
		library.

LINKS		The list of binary links; should be full pathnames, the
		linked-to file coming first, followed by the linked
		file.  The files are hard-linked.  For example, to link
		/bin/test and /bin/[, use:

			LINKS=	/bin/test /bin/[

LINKOWN		Owner of links created with LINKS [${LIBOWN}].

LINKGRP		Group of links created with LINKS [${LIBGRP}].

LINKMODE	Mode of links created with LINKS [${LIBMODE}].

MAN		The manual pages to be installed. See bsd.man.mk for more
		details.

SHLIB		Like LIB but only builds a shared library.

SHLIB_CXX	Like LIB_CXX but only builds a shared library.

SHLIB_LDSCRIPT	Template file to generate shared library linker script.
		If not defined, a simple symlink is created to the real
		shared object.

SRCS		List of source files to build the library.  Suffix types
		.s, .c, and .f are supported.  Note, .s files are preferred
		to .c files of the same name.  (This is not the default for
		versions of make.)

The include file <bsd.lib.mk> includes the file named "../Makefile.inc"
if it exists, as well as the include file <bsd.man.mk>.

Libraries are ranlib'd before installation.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

The include file <bsd.test.mk> handles building one or more test programs
intended to be used in the FreeBSD Test Suite under /usr/tests/.

It has seven targets:

	all:
		build the test programs.
	check:
		runs the test programs with kyua test.

		The beforecheck and aftercheck targets will be invoked, if
		defined, to execute commands before and after the realcheck
		target has been executed, respectively.

		The devel/kyua package must be installed before invoking this
		target.
	clean:
		remove the test programs and any object files.
	cleandir:
		remove all of the files removed by the target clean, as
		well as .depend and tags.
	depend:
		make the dependencies for the source files, and store
		them in the file .depend.
	install:
                install the test programs and their data files; if the
                Makefile does not itself define the target install, the
                targets beforeinstall and afterinstall may also be used
                to cause actions immediately before and after the
                install target is executed.
	tags:
		create a tags file for the source files.

It sets/uses the following variables, among many others:

ATF_TESTS_C	The names of the ATF C test programs to build.

ATF_TESTS_CXX	The names of the ATF C++ test programs to build.

ATF_TESTS_SH	The names of the ATF sh test programs to build.

GTESTS		The names of the GoogleTest test programs to build.

KYUAFILE	If 'auto' (the default), generate a Kyuafile out of the
		test programs defined in the Makefile.  If 'yes', then a
		manually-crafted Kyuafile must be supplied with the
		sources.  If 'no', no Kyuafile is installed (useful for
		subdirectories providing helper programs or data files
		only).

LOCALBASE	The --prefix for the kyua package.

		The value of LOCALBASE defaults to /usr/local .

NOT_FOR_TEST_SUITE
		If defined, none of the built test programs get
		installed under /usr/tests/ and no Kyuafile is
		automatically generated.  Should not be used within the
		FreeBSD source tree but is provided for the benefit of
		third-parties.

PLAIN_TESTS_C	The names of the plain (legacy) programs to build.

PLAIN_TESTS_CXX	The names of the plain (legacy) test programs to build.

PLAIN_TESTS_PORCH	The names of the plain (legacy) porch(1)-based
		test programs to build.

PLAIN_TESTS_SH	The names of the plain (legacy) test programs to build.

TAP_PERL_INTERPRETER
		Path to the Perl interpreter to be used for
		TAP-compliant test programs that are written in Perl.
		Refer to TAP_TESTS_PERL for details.

TAP_TESTS_C	The names of the TAP-compliant C test programs to build.

TAP_TESTS_CXX	The names of the TAP-compliant C++ test programs to
		build.

TAP_TESTS_PERL	The names of the TAP-compliant Perl test programs to
		build.  The corresponding source files should end with
		the .pl extension; the test program is marked as
		requiring Perl; and TAP_PERL_INTERPRETER is used in the
		built scripts as the interpreter of choice.

TAP_TESTS_SH	The names of the TAP-compliant sh test programs to
		build.

TESTSBASE	Installation prefix for tests. Defaults to /usr/tests

TESTSDIR	Path to the installed tests.  Must be a subdirectory of
		TESTSBASE and the subpath should match the relative
		location of the tests within the src tree.

		The value of TESTSDIR defaults to
		${TESTSBASE}/${RELDIR:H} , e.g. /usr/tests/bin/ls when
		included from bin/ls/tests .

TESTS_SUBDIRS	List of subdirectories containing tests into which to
		recurse.  Differs from SUBDIR in that these directories
		get registered into the automatically-generated
		Kyuafile (if any).

The actual building of the test programs is performed by <bsd.prog.mk>.
Please see the documentation above for this other file for additional
details on the behavior of <bsd.test.mk>.