Remove $FreeBSD$: one-line sh pattern

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

hexdump: Partial lines cannot be repetitions of earlier lines.

When checking for repetitions of earlier lines, we compare the
first nread bytes of the line against the saved line. However,
when we read a partial line, it should never be treated as a
repetition of an earlier line, even if the first bytes match.

This change fixes a bug where a partial line could be
incorrectly identified as a repetition of an earlier line.

Reported-by: Mark Adler <madler@alumni.caltech.edu>
PR: 118723
Reviewed-by: emaste
MFC-after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D40471

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

hexdump: tests: take into account byte order

Hexdump test was failling on big endian systems when testing decimal, octal
and hexa outputs as the tests were designed on a little endian system. This
revision adds the two distinct flavors of output expected and determines at
runtime which to compare against.

Submitted by: Renato Riolino <renato.riolino_eldorado.org.br>
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23191

hexdump(1): Exit gracefully on format strings missing conversion

PR: 237263
Submitted by: Bojan Petrovic <bojan_petrovic AT fastmail.fm>

Standardize SPDX tag on files I've added

hexdump: Remove expected test failures for now succeeding tests

r323990 fixed the -s flag breakage reported by PR 219173. Mark the
corresponding hexdump tests accordingly, since they should now both succeed.

PR: 222781
Reported by: ngie
Reviewed by: emaste, ngie
Approved by: emaste (mentor)
Differential Revision: https://reviews.freebsd.org/D12590

Add some basic tests for hexdump(1)'s various output flags. Formatting
tests are omitted for this initial run as there are still some bugs to work
out there.

This covers -s flag testing on devices and non-devices that would have
caught breakage found in PR 219173 as well as other subtle breakage caused
locally.

Reviewed by: cem, ngie
Approved by: cem (acting co-mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D11279