MFC r347445, r353961: dtc build issues

r347445:
Fix build issue with clang 8.0.1

The algorithm header is needed to use std::remove_if

r353961:
exit requires stdlib.h to be included to use.

FreeBSD 10.3 requires this, and dtc is a bootstrap tool so it needs to
compile
there.

MFC r345628: dtc(1): Update to 1a79f5f26631

Highlights:
- Bugfix for order in which /delete-node/ and /delete-property/ are
processed [0]
- /omit-if-no-ref/ support has been added (used only by U-Boot at this
point, in theory)
- GPL dtc compat version bumped to 1.4.7
- Various small fixes and compatibility improvements

MFC r337964, r338232: dtc(1) updates

r337964:
dtc(1): Update to 97d2d5715eeb45108cc60367fdf6bd5b2046b050

Notable fixes:
- Overlays may now be generated properly without -@
- /__local_fixups__ were not including unit address in their structure
- The error reporting a magic token was misleading, reporting
"Bad magic token in header. Got d00dfeed expected 0xd00dfeed"
if the token was missing. This has been split out into a separate message.

r338232:
dtc(1): Update to 0892ec7; HACKING and implicit header fixes

Fixes courtesy of arichardson and jmg:
- HACKING was pointing to the wrong place
- Added headers were being relied on implicitly, but libstdc++ did not
comply with the unspoken wishes of dtc.

MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

MFC r306806, r313709, r317058, r317060

r306806 by emaste:
Improvements to BSD-licensed DTC.

- Numerous crash and bug fixes
- Improved warning and error messages
- Permit multiple labels on nodes and properties
- Fix node@address references
- Add support for /delete-node/
- Consume whitespace after a node
- Read the next token before the second /memreserve/
- Fix parsing of whitespace
- Clean up /delete-node/ and add support for /delete-property/
- Handle /delete-node/ specifying a unit address

Obtained from: https://github.com/davidchisnall/dtc @df5ede4

r313709 by dim:
Fix build of BSD dtc when NDEBUG is defined (MK_ASSERT_DEBUG=no):
* Initialize correct parent in binary_operator's constructor.
* Include <errno.h> explicitly, otherwise errno is undefined (without
NDEBUG, this is accidentally 'fixed' by including <iostream>).

Reported by: matteo

r317058 by emaste:
dtc: remove unused (since r306806) string.hh

r317060 by emaste:
dtc: update to upstream 227d6a3

- Report missing includes at the correct location.
- Add initial support for the -@ option emitting a symbol table.
- Add support for running tests with and without -@
- Add support for generating __fixups__ and __local_fixups__
- Attach the to-string transform to the node path.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Lots of improvements to the BSD-licensed dtc

- Various fixes to includes (including recursive includes)
- Lots of testing that the output exactly matches GPL'd dtc
- Lots of bug fixes to merging
- Fix incorrect mmap usage
- Ad-hoc memory management replaced with C++11 unique_ptr and similar

Patrick Wildt has successfully run many (all?) of the GPL dtc test suite.

Explicitly include headers that are implicitly included by libstdc++. Fixes
building dtc with libc++.

Import new (BSDL) device tree compiler. Now built by default, so that it can't
be used on the host system (and not installed on the device, if required). The
GPL'd one is still available if there are any devices that need it (make
universe passes with it, including kernels that use fdt, but there may be some
out-of-tree ones). WITH_GPL_DTC can be used to select the old one, for now.

Probably won't be MFC'd, but we'll remove the GPL'd version in head after the
new one has had a lot more testing and ship it in 10.0.