Remove $FreeBSD$: one-line sh pattern

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

Bump WARNS from 1 to 3 after recent commits to fix warnings in the
directory.

Tested with: clang 4.0, gcc 4.2.1, gcc 6.3.0
MFC after: 1 week
Sponsored by: Dell EMC Isilon

Sort make variables to suit style.Makefile(5)

This is being done prior to functional changes.

MFC after: 3 days
Sponsored by: Dell EMC Isilon

Increase WARNS for nss tests

ATF tests have a default WARNS of 0, unlike other usermode programs.

Reviewed by: ngie
MFC after: 3 weeks
Sponsored by: Spectra Logic Corporation
Differential Revision: https://reviews.freebsd.org/D9933

Merge ^/user/ngie/release-pkg-fix-tests to unbreak how test files are installed
after r298107

Summary of changes:

- Replace all instances of FILES/TESTS with ${PACKAGE}FILES. This ensures that
namespacing is kept with FILES appropriately, and that this shouldn't need
to be repeated if the namespace changes -- only the definition of PACKAGE
needs to be changed
- Allow PACKAGE to be overridden by callers instead of forcing it to always be
`tests`. In the event we get to the point where things can be split up
enough in the base system, it would make more sense to group the tests
with the blocks they're a part of, e.g. byacc with byacc-tests, etc
- Remove PACKAGE definitions where possible, i.e. where FILES wasn't used
previously.
- Remove unnecessary TESTSPACKAGE definitions; this has been elided into
bsd.tests.mk
- Remove unnecessary BINDIRs used previously with ${PACKAGE}FILES;
${PACKAGE}FILESDIR is now automatically defined in bsd.test.mk.
- Fix installation of files under data/ subdirectories in lib/libc/tests/hash
and lib/libc/tests/net/getaddrinfo
- Remove unnecessary .include <bsd.own.mk>s (some opportunistic cleanup)

Document the proposed changes in share/examples/tests/tests/... via examples
so it's clear that ${PACKAGES}FILES is the suggested way forward in terms of
replacing FILES. share/mk/bsd.README didn't seem like the appropriate method
of communicating that info.

MFC after: never probably
X-MFC with: r298107
PR: 209114
Relnotes: yes
Tested with: buildworld, installworld, checkworld; buildworld, packageworld
Sponsored by: EMC / Isilon Storage Division

First pass to fix the 'tests' packages.

Sponsored by: The FreeBSD Foundation

Integrate tools/regression/lib/libc/nss into the FreeBSD test suite as
lib/libc/tests/nss

- Convert the testcases to ATF
- Do some style(9) cleanups:
-- Sort headers
-- Apply indentation fixes
-- Remove superfluous parentheses
- Explicitly print out debug printfs for use with `kyua {debug,report}`; for
items that were overly noisy, they've been put behind #ifdef DEBUG
conditionals
- Fix some format strings

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division