Remove $FreeBSD$: one-line sh pattern

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

Do a sweep and remove most WARNS=6 settings

Repeating the default WARNS here makes it slightly more difficult to
experiment with default WARNS changes, e.g. if we did something absolutely
bananas and introduced a WARNS=7 and wanted to try lifting the default to
that.

Drop most of them; there is one in the blake2 kernel module, but I suspect
it should be dropped -- the default WARNS in the rest of the build doesn't
currently apply to kernel modules, and I haven't put too much thought into
whether it makes sense to make it so.

Increase WARNS for rtld-elf tests

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

Reviewed by: ngie, julian
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

Fix LDADD/DPADD that should be LIBADD.

Sponsored by: EMC / Isilon Storage Division

Similar to r269506, fix LIBDIR to not duplicate TESTSDIR

Phabric: D536
Reviewed by: jmmv
Approved by: jmmv (mentor)
Sponsored by: EMC / Isilon Storage Division

libpythagoras needs libm.

This fixes "make tinderbox" failures on various architectures when
WITH_TESTS=yes is enabled. Problem introduced in r267679.

Test RTLD's new LD_LIBRARY_PATH_FDS variable.

Test LD_LIBRARY_PATH_FDS by linking a binary that requires a shared
library that isn't in any of the usual search paths. Ensure this fails
when we don't supply LD_LIBRARY_PATH_FDS or we pass invalid information
in it. Ensure it works when we pass the correct directory in various
places in the variable.

Approved by: rwatson (mentor)
MFC after: 3 weeks
Sponsored by: DARPA/AFRL