Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

dtc: re-apply r353961, r354115

I missed in final review of r357923's diff that these ones hadn't yet been
sent upstream and inadvertently reverted them. =-( Re-apply now.

Pull in latest fixes from dtc, up to 0060471

This includes a small battery of /memreserve/ fixes to make sure dtc is
properly writing these regions into the output file and reading them back
out.

As of this update, dtc will now also assume common defaults for -I/-O if
only one is specified; namely, dts for one implies dtb for the other and
vice versa (Requested by: jhibbits, preserves GPL dtc behavior too).

MFC after: 1 week

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.

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

Reported by: strejda [0]
MFC after: 1 week

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.

MFC after: 1 week

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.

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

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.