MFC r348498: libatf: remove workaround not required after atf >= 0.18 update

lib/atf/libatf-c/tests/Makefile added the -Wno-duplicate-decl-specifier
due to an issue with an old version of ATF. ATF has long since been
updated to a version with the fix so the workaround is no longer
necessary.

Found during review for PR 236889.

PR: 236889

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

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

Fix including Kyuafile in packaged base system.

Fix a related typo while here.

Note, this change results in the Kyuafile inclusion in the runtime
package, which needs to be fixed, however addresses the PR as far
as I can tell in my tests.

PR: 209114
Submitted by: ngie
Sponsored by: The FreeBSD Foundation

Merge the projects/release-pkg branch to head.

This allows packaging the base system with pkg(8), including
but not limited to providing the ability to provide upstream
binary update possibilities for non-tier-1 architectures.

This merge is a requirement of the 11.0-RELEASE, and as such,
thank you to everyone that has tested the project branch.

Documentation in build(7) etc. is still somewhat sparse, but
updates to those parts will follow.

Sponsored by: The FreeBSD Foundation

DIRDEPS_BUILD: Connect MK_TESTS.

Sponsored by: EMC / Isilon Storage Division

Refactor the test/ Makefiles after recent changes to bsd.test.mk (r289158) and
netbsd-tests.test.mk (r289151)

- Eliminate explicit OBJTOP/SRCTOP setting
- Convert all ad hoc NetBSD test integration over to netbsd-tests.test.mk
- Remove unnecessary TESTSDIR setting
- Use SRCTOP where possible for clarity

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Divison

MFV: Import atf-0.21.

Change libatf-c and libatf-c++ to be private libraries.

We should not be leaking these interfaces to the outside world given
that it's much easier for third-party components to use the devel/atf
package from ports.

As a side-effect, we can also drop the ATF pkgconfig and aclocal files
from the base system. Nothing in the base system needs these, and it
was quite ugly to have to get them installed only so that a few ports
could build. The offending ports have been fixed to depend on
devel/atf explicitly.

Reviewed by: bapt

Make bsd.test.mk the only public mk fragment for the building of tests.

Change {atf,plain,tap}.test.mk to be internal implementation details of
bsd.test.mk. Makefiles that build tests should now only include bsd.test.mk
and declaratively specify what they want to build, without worrying about
the internal implementation of the mk files.

The reason for this change is to permit building test programs of different
interfaces from a single directory, which is something I had a need for
while porting tests over from src/tools/regression/.

Additionally, this change makes it possible to perform some other requested
changes to bsd.test.mk in an easier manner. Coming soon.

MFV: Import atf-0.20.

Respect the original layout of the atf-{c,c++} tests.

Put test programs for internal modules into a 'detail' subdirectory of the
libatf-c and libatf-c++ test directories, just as the upstream distribution
does. This is necessary because the tests assume such layout to find the
process_helper program, and currently fail because of this divergence.

MFC after: 1 week

To avoid having to explicitly test COMPILER_TYPE for setting
clang-specific or gcc-specific flags, introduce the following new
variables for use in Makefiles:

CFLAGS.clang
CFLAGS.gcc
CXXFLAGS.clang
CXXFLAGS.gcc

In bsd.sys.mk, these get appended to the regular CFLAGS or CXXFLAGS for
the right compiler.

MFC after: 1 week

MFV: Import atf-0.18.

Approved by: rpaulo (mentor)

Fix the build of some ATF tests.

When building various programs from a single Makefile, program-specific
variables are of the form <VAR>.<PROG>, not <VAR>_<PROG>. Fix this
obvious typo to fix the build when WITH_TESTS=yes.

I am not sure how this ever worked before given that manual inspection
of bsd.progs.mk clearly shows that the expected character between the
two components is a dot and not an underscore... but I suspect the
changes in r258095 exposed this oddity.

Approved by: rpaulo (mentor)

Build and install the atf tests.

Reviewed by: freebsd-testing
Approved by: rpaulo (mentor)