Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Allow site.*.mk to augment local.*.mk and src.*.mk

Add some extra customization points so that FreeBSD build
can be adapted to local requirements.
We use these to minimize changes to share/mk

Reviewed by: stevek
Sponsored by: Juniper Networks, Inc.
Differential Revision: https://reviews.freebsd.org/D37617

build target triple variable from sys/conf/newvers.sh

Retrieve FreeBSD revision number directly from sys/conf/newvers.sh
when building the compiler target triple value, avoiding manual
intervention on other files every new release.

Reviewed by: imp
MFC after: 2 months
Sponsored by: Instituto de Pesquisas Eldorado (eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D34429

META_MODE: Allow 'make all install' to work with filemon.

Filemon will add the ability to ignore the cookie if the installed file is
missing. Without filemon that's not possible though so if the cookie is present
an the command unchanged then the install wouldn't run.

Sponsored by: DellEMC
MFC after: 2 weeks

Ignore MAKEOBJDIRPREFIX from src-env.conf in sub-makes.

A sub-make, such as in 'make buildworld', may want to override MAKEOBJDIRPREFIX
but is unable to do so if src-env.conf is forcing it to another value. Without
using '?=' the sub-make may use the wrong .OBJDIR.

Reported by: eadler
Sponsored by: Dell EMC

Deal with bmake-20170301 no longer resolving -C like it used to.

Several checks assume .CURDIR is resolved, such as for determining RELDIR from
SRCTOP/.CURDIR. If -C is used then the path is no longer resolved like it was
before which is problematic for symlinked source trees. A similar change was
also made to ports post bmake-20170301.

This fixes 'make -C <symlinked path> buildworld' using the wrong OBJDIR.

Reported by: rstone
Sponsored by: Dell EMC

Evaluate options after including src-env.conf and before Makefile.sys.inc.

Fixes top-level breakage in r325974.

Pointyhat to: bdrewery
Sponsored by: Dell

Include Makefile.sys.inc if possible for top-level only.

This will allow disabling some things like AUTO_OBJ early if not needed for the
directory/targets, without putting special logic into share/mk/*.sys.mk.

Sponsored by: Dell

Add option UNIFIED_OBJDIR, on by default, which moves the default build OBJDIR.

This changes the build OBJDIR from the older style of /usr/obj/<srcdir> for
native builds, and /usr/obj/<target>.<target_arch>/<srcdir> for cross builds to
a new simpler format of /usr/obj/<srcdir>/<target>.<target_arch>. This
new format is used regardless of cross or native build. It allows
easier management of multiple source tree object directories.

The UNIFIED_OBJDIR option will be removed and its feature made permanent
for the 12.0 release.

Relnotes: yes (don't note UNIFIED_OBJDIR option since it will be removed)
Prior work: D3711 D874
Reviewed by: gjb, sjg
Discussed at: https://lists.freebsd.org/pipermail/freebsd-arch/2016-May/017805.html
Discussed with: emaste
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12840

Add RELOBJTOP and RELSRCTOP for relative paths.

RELSRCTOP is likely not as useful since make will always be running from
inside of .OBJDIR and using something like ${.CURDIR}/${RELSRCTOP} is
not redundant for ${SRCTOP}.

Sponsored by: Dell EMC Isilon

WITH_META_MODE: Don't let subdir traversals for 'make install' re-enable meta mode.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Fix MAKESYSPATH not being sent to sub-makes after r266566.

Because bmake defaults to .../share/mk now, this code was not doing anything
to help objdir builds (such as the rescue build). Export the same default.

Sponsored by: EMC / Isilon Storage Division

WITH_META_MODE: Disable for 'make install' from top-level.

See r298220 for more explanation. We don't want to prevent installing
if a cookie exists for the install target.

Sponsored by: EMC / Isilon Storage Division

RELDIR is useful without META_MODE. Always define it.

It is the CURDIR without the SRC base location in it.

Sponsored by: EMC / Isilon Storage Division

Move include of make.conf back to its old position.

This means moving include of local.sys.mk and src.sys.mk too.
Introduce new includes to take the early slot, for the purpose
of being able to influence toolchains and the like.

Differential Revision: D2860
Reviewed by: imp