Remove $FreeBSD$: one-line sh pattern

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

pkgbase: Create a FreeBSD-elftoolchain package

It contain all the binaries and libs from the elftoolchain contrib
project except for libelf which is used everywhere.
All of those tools are never used by the average user.

Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D38224

libelftc: Add MLINKS.

Reviewed by: emaste
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20474

Install the lib/libelftc manpages

Some other manpages, e.g. c++filt reference these

MFC after: 1 week

Use the in-tree sys/elf_common.h to build libelftc.

This fixes build failures on older releases that lack various
definitions such as EM_AARCH64 (which was unfixed before this).

Revert all of the recent compatibility changes that worked around this
problem.

This uses the same method of using the in-tree header as lib/libelf,
lib/libdwarf and usr.bin/readelf.

Reviewed by: emaste
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D6734

elftoolchain: Use ${SRCTOP} for the top of the FreeBSD tree

It's provided by sys.mk so there's no need to derive it from ${.CURDIR}.

Suggested by: ngie
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5998

Replace ${CURDIR}/../.. with ${CURDIR:H:H} in elftoolchain

This produces a nicer path in debug info and build logs.

MFC after: 1 week
Sponsored by: The FreeBSD Foundation

First pass through library packaging.

Sponsored by: The FreeBSD Foundation

Use MAN= to specify that no man page is provided

NO_MAN is deprecated.

Reviewed by: imp

Build infrastructure for elftoolchain tools

Set WITH_ELFTOOLCHAIN_TOOLS in src.conf to use the elftoolchain version
of the following tools:

* addr2line
* elfcopy (strip / mcs)
* nm
* size
* strings

Reviewed by: bapt (earlier version)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D1224