Deprecate extsrc/, EXTSRCSRCDIR, MKEXTSRC

Remove support for building extsrc/:
1. Makefile: remove do-extsrc target.
2. build.sh: remove options -y and -Y extsrcdir.
3. distrib/sets: remove support for extsrc in various tools
including the options -L ext and -y, and the extsrc sets.
4. doc/BUILDING.mdoc: remove docs for extsrc/, EXTSRCSRCDIR, MKEXTSRC (etc)
5. bsd.own.mk and various Makefiles: remove support for extsrc/,
EXTSRCSRCDIR, MKEXTSRC.

As proposed on tech-kern and tech-userlevel on 2022-01-07
and followed up on 2022-08-21.

build system: Revert all the recent additions of MK[...] knobs that
allow conditionally disabling the building of certain user space
programs in the 'base' set.

There is not enough consensus that this is the right way and a few
people had strong objections, see source-changes-d@.

mk: Allow setting MKDHCPD=no to build base without the ISC DHCP server,
useful for embedded images that don't need to act as one.

Handle mipsn64

Revert accidental part of prior

Remove in-kernel handling of Router Advertisements

This is much better handled by a user-land tool.
Proposed on tech-net here:
https://mail-index.netbsd.org/tech-net/2020/04/22/msg007766.html

Note that the ioctl SIOCGIFINFO_IN6 no longer sets flags. That now
needs to be done using the pre-existing SIOCSIFINFO_FLAGS ioctl.

Compat is fully provided where it makes sense, but trying to turn on
RA handling will obviously throw an error as it no longer exists.

Note that if you use IPv6 temporary addresses, this now needs to be
turned on in dhcpcd.conf(5) rather than in sysctl.conf(5).

Separate devicetree .dts -> .dtb building from kernel builds. They are now
part of a separate set, "dtb.tgz", and only built when MKDTB=yes. This
defaults to yes for earmv[67]* and aarch64, and no everywhere else.

remove the recently added files or added entries for what is
./usr/include/$MACHINE and automatically add it.

add sun68k for sun2/sun3. tested on about 12 platforms.

there may be more failures to figure out but this should make
them all special cases rather than always expected cases.

fortunately, most builds don't see to hit these issues for
reasons i haven't determined yet.

ensure that all include dirs are created before make includes runs.

separate the compat vs per-arch -ness of the mtree lists. merge the
mips64 mtree files into a single file.

separate out the arch-specific and compat-specific subdirs.
put compat stuff in NetBSD.compat.$MACHINE_ARCH, and normal
stuff in NetBSD.dist.$MACHINE/MACHINE_ARCH, etc.

probably need at at more files for sh3, mips, ppc, sparc,
m68k, arm, ia64, etc., as every port has port- or arch-
specific header subdirectory.

move ./usr/include/dev/iscsi into NetBSD.dist.iscsi that is only
included if MKISCSI != no.

branches: 1.37.4;
merge the rest of sbmips into evbmips. install the stand files in
/usr/mdec/sbmips/ and document them in installboot(8) even though
it isn't really ported yet. also build the SBMIPS kernels.

unfortunately, sbmips has been broken since mips64 merge, but the
fix can happen in the evbmips version, which we might merge into
the older trees anyway.

XXX: releng can turn off sbmips* builds now for -current.

branches: 1.36.6;
An awk file is not a directory.

branches: 1.35.2;
Mark phone so we rebuild every time.

Don't run .BEGIN if we are cleaning or making obj.

Avoid most of the .CURDIR hackery by letting make locate the files.

make sure the build dist files are build before we try to use them.

don't give NetBSD.dist.tmp any inputs, as then it won't rebuild ever
unless they change, and we want to rebuild based upon what inputs are
present, not when they were last touched.

this fixes update builds that switch options that change the dirlist
like MKX11 or MKCOMPAT, restoring a portion of rev 1.14.

note that some opertions like turning off MKX11=yes will also require
a fresh DESTDIR, in addition to this fix. there may be more issues
remaining, but i am now able to enable MKX11=yes successfully without
any other change.

Handle the contents of /usr/lib/dtrace so a MKDTRACE=yes release completes.

remove the xfree86 reachover makefiles and the vast majority of
the support in the rest of the source tree.

X11 sets could use some cleaning up perhaps (just deletion, as
we've never really marked the old X11R6 as obsolete for native
xorg using platforms so far either.)

Guard a few $MK... != "no" tests by an additional defined(MK...) clause
and make the emit_dist_file target depend on EXTRA_DIST_FILES.
Part of fixing PR toolchain/50004.

Need to test for MKCOMPATX11

Support building the xorg X11 libraries under MKCOMPAT.
Add XORG_MACHINE_ARCH to compat's bsd.*.mk
Turn xorg makekeys and makestrs into real host tools which are installed into
${TOOLSDIR}

Rework this to auto generate the compat directories using a template
and the information from compat/archdirs.mk. Also add suport MKCOMPATTESTS
and process the NetBSD.dist.tests to generate appropriate compat directories.

silence is golden

Add MKCOMPAT support for earm

branches: 1.22.2; 1.22.4; 1.22.8;
Revert previous now that "make cleandir" uses bsd.clean.mk to clean
both the obj dir and the src dir.

Use ${.OBJDIR}/NetBSD.dist.tmp instead of just NetBSD.dist.tmp.
This fixes a problem in which NetBSD.dist.tmp had been created in
the SRCDIR by an earlier build (performed without an OBJDIR), and
the existence of the file in the SRCDIR confused a subsequent build
(performed with an OBJDIR).

Typo fix.

branches: 1.19.2;
if MKCOMPAT != "no", don't include the MD files for now -- they're only
used for compat right now. we should fix this better later.

Make tests set generation optional, skipped for MKATF=no build.

Describe in a comment what the emit_dist_file target is for.

Under some circumstances, ${TOOL_CAT} may refer to an executable
that does not exist. As a stopgap fix, use cat(1) instead of
${TOOL_CAT} in emit_dist_file.

Do not try in postinstall(8) to replicate the code in etc/mtree/Makefile
that assembles /etc/mtree/NetBSD.dist. Instead, use the Makefile's
new target, emit_dist_file, to assemble the correct NetBSD.dist.

Previously, 'postinstall -m amd64 -s $SRC_TOP' would install a
NetBSD.dist that was missing /usr/lib/i386/ et cetera.

also clean up NetBSD.dist.tmp as if a second build is done without the
NetBSD.dist changing, the tmp file will remain.

Make sure NetBSD.dist is updated when MKX11 is changed across update builds.

create /usr/lib/{i386,sparc}{,/security,/i18n} here, where they belong.

replace NETBSD_DIST_X11_FILE and NETBSD_DIST_EXTSRC_FILE with EXTRA_DIST_FILES

Support "extsrc", externally added programs and libraries. Users can write
their own reach-overs, cross-build, install, and get set files just like base
and X11 / X.org. (These sets are not included as TNF releases.)

remove some unnecessary .OBJDIR prefixes in make targets
being here, add NetBSD.dist to CLEANFILES

Fixed NetBSD.dist target

Fixed build with read-only source tree.

Allow builds without X11 to succeed. The previous change when used
in this situation caused the contents of ${.CURDIR} to be cat'ed
into the generated NetBSD.dist mtree spec file, resulting in
${DESTDIR}/var/yp/binding/<garbage> being created, causing set list
check failure at the end of the build.

- do not create X11 subdirs always anymore

- we now only create them when building X11, and only create the ones
we need (X11R6 xor X11R7)

- all these subdirs are now in the xbase set

- move the logic for running mtree into etc/mtree/Makefile

- split NetBSD.dist into 3 files, and have the build and postinstall handle
creating a possibly merged one. we still have a single installed file
called "NetBSD.dist".

branches: 1.5.40;
Consistently use CONFIGFILES & CONFIGLINKS (which enable the 'configinstall'
target) instead of using home-grown 'distribution' targets or using
FILES with the 'install' target.
Add some etc/ subdir Makefiles where appropriate.

XXX: some of etc/Makefile install-etc-files could be converted to CONFIGFILES.

- in <bsd.files.mk>, don't clear FILES after using it, as that prevents
make -V FILES
from being useful (and given that every other variable can be
extracted using make -V, the behaviour was unusually inconsistent
given that the original reason for clearing it doesn't seem to be
relevant anymore)
- use <bsd.prog.mk> instead of directly including <bsd.files.mk>
(and possibly <bsd.man.mk> or <bsd.own.mk>)
- remove obsolete NOPROG

src/etc/mtree/BSD.x11.dist moved to pkgsrc/mk/NetBSD.x11.dist by
Repository Copy.

src/etc/mtree/BSD.pkg.dist moved to pkgsrc/mk/NetBSD.pkg.dist by
Repository Copy.

create etc/mtree/Makefile and let it deal with what files are installed.