Remove $FreeBSD$: one-line sh pattern

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

googletest: remove unused auto_ptr warning suppression

lib/googletest used -Wno-deprecated-declarations to silence warnings
about usage of deprecated std::auto_ptr, but auto_ptr is not (now) used
anywhere in googletest.

Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D37561

googletest: Silence warnings about deprecated implicit copy constructors

Our copy of googletest is rather stale, and causes a number of -Werror
warnings about implicit copy constructor definitions being deprecated,
because several classes have user-declared copy assignment operators.
Silence the warnings until we either upgrade or remove googletest.

MFC after: 3 days

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.

Another round of attempting to squelch -Wdeprecated-declarations, which
has become very trigger-happy with libc++ 9.0.0.

It does not help that gcc's implementation of this warning is even more
trigger-happy, in the sense that it already warns on the declaration
itself, not when you are using it. This is very annoying with our use
of -Wsystem-headers. That should really be disabled for gcc.

Move `NO_WTHREAD_SAFETY` to googletest.test.inc.mk

This variable is necessary to compile with googletest at a global level. Move
it there.

Correct gmock/gtest expectations w.r.t. C++11/RTTI

Long story short, some of the tests were failing because they expected either
dynamic_cast or RTTI to be functional and it wasn't.

Move all common CXXFLAGS out to googletest.test.inc.mk and reference it from
googletest.test.mk and .../googletest/Makefile.inc

Add more port-related flags to Makefile.inc

Merge build glue for libraries and tests done on github

I need to doublecheck my work vs the port, but I believe that this covers the
initial integration of all upstream tests.

Ref: https://github.com/ngie-eign/freebsd/tree/googletest-integration