Fix GoogleTest 1.14.0 import

- Prune headers and tests no longer installed after the upgrade.
- Remove GoogleTest-related files when MK_GOOGLETEST == no.
- Disable `-Werror` with gcc to unbreak the gcc12 CI run with
`lib/googletest`. Any issues found by g++ will be filed
upstream and hopefully resolved in a future version.
- Remove clang -Werror issues which are resolved in version 1.14.0 to
avoid masking valid issues.

MFC after: 1 week
MFC with: 28f6c2f292806bf31230a959bc4b19d7081669a7

Remove $FreeBSD$: one-line sh pattern

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

Import GoogleTest 1.14.0

GoogleTest 1.14.0 now requires C++14 to build. Change
`googletest.test.inc.mk` to reflect this requirement.

Adjust the build integration logic to handle the new version of
GoogleTest (add/remove headers/sources as needed).

Tighten down warnings via `CXXFLAGS.clang` instead of ignoring all
warnings. Some new warnings snuck in after I did my last round of fix
submissions upstream.

Also address some overlinking added in the previous version import by
removing superfluous libraries.

===============================

Expect WhenDynamicCastToTest.AmbiguousCast to fail

This change reapplies the expected failure from 1.10.0.

Ref: https://github.com/google/googletest/issues/2172

MFC after: 2 weeks
Reviewed by: asomers, emaste
Differential Revision: https://reviews.freebsd.org/D41399

Merge commit '8ef491440fcaec96f899d73e08873426c78583a4' into googletest-v1.14.0-import

Work around two -Werror warning issues in googletest, which have been
solved upstream in the mean time.

The first issue is because one of googletest's generated headers contain
classes with a user-declared copy assignment operator, but rely on the
generation by the compiler of an implicit copy constructor, which is now
deprecated:

/usr/obj/usr/src/amd64.amd64/tmp/usr/include/private/gtest/internal/gtest-param-util-generated.h:5284:8: error: definition of implicit copy constructor for 'CartesianProductHolder3<testing::internal::ParamGenerator<bool>, testing::internal::ValueArray3<int, int, int>, testing::internal::ValueArray4<cache_mode, cache_mode, cache_mode, cache_mode> >' is deprecated because it has a user-declared copy assignment operator [-Werror,-Wdeprecated-copy]
void operator=(const CartesianProductHolder3& other);
^
/usr/obj/usr/src/amd64.amd64/tmp/usr/include/private/gtest/gtest-param-test.h:1277:10: note: in implicit copy constructor for 'testing::internal::CartesianProductHolder3<testing::internal::ParamGenerator<bool>, testing::internal::ValueArray3<int, int, int>, testing::internal::ValueArray4<cache_mode, cache_mode, cache_mode, cache_mode> >' first required here
return internal::CartesianProductHolder3<Generator1, Generator2, Generator3>(
^
/usr/src/tests/sys/fs/fusefs/io.cc:534:2: note: in instantiation of function template specialization 'testing::Combine<testing::internal::ParamGenerator<bool>, testing::internal::ValueArray3<int, int, int>, testing::internal::ValueArray4<cache_mode, cache_mode, cache_mode, cache_mode> >' requested here
Combine(Bool(), /* async read */
^

For now, silence the warning using -Wno-deprecated-copy.

The second issue is because one of the googlemock test programs attempts
to use "unsigned wchar_t" and "signed wchar_t", which are non-standard
and at best, hazily defined:

contrib/googletest/googlemock/test/gmock-actions_test.cc:111:37: error: 'wchar_t' cannot be signed or unsigned [-Wsigned-unsigned-wchar]
EXPECT_EQ(0U, BuiltInDefaultValue<unsigned wchar_t>::Get());
^
contrib/googletest/googlemock/test/gmock-actions_test.cc:112:36: error: 'wchar_t' cannot be signed or unsigned [-Wsigned-unsigned-wchar]
EXPECT_EQ(0, BuiltInDefaultValue<signed wchar_t>::Get());
^

For now, silence the warning using -Wno-signed-unsigned-wchar.

MFC after: 3 days

Fix up CXXSTD support originally added in r345708

r345708 worked for the base system, but unfortunately, caused a lot of
disruption for third-party packages that relied on C++, since bsd.sys.mk is
used by applications outside the base system. The defaults picked didn't match
the compiler's defaults and broke some builds that didn't specify a standard,
as well as some that overrode the value by setting `-std=gnu++14` (for
example) manually.

This change takes a more relaxed approach to appending `-std=${CXXSTD}` to
CXXFLAGS, by only doing so when the value is specified, as opposed to
overriding the standard set by an end-user. This avoids the need for having
to bake NOP default into bsd.sys.mk for supported compiler-toolchain
versions.

In order to make this change possible, add CXXSTD to Makefile snippets which
relied on the default value (c++11) added in r345708.

MFC after: 2 weeks
MFC with: r345708, r346574
Reviewed by: emaste
Reported by: jbeich
Differential Revision: https://reviews.freebsd.org/D19895 (as part of a larger change)

Standardize `-std=c++* as `CXXSTD`

CXXSTD was added as the C++ analogue to CSTD.

CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.

This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.

As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.

Notes:

This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.

Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:

Before this commit:
```
CXXFLAGS+= -std=c++14
```

After this commit:
```
CXXSTD= c++14
```

Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
MFC with: r345203, r345704, r345705
Relnotes: yes
Tested with: make tinderbox
Differential Revision: https://reviews.freebsd.org/D19732

Revert r345706: the third time will be the charm

When a review is closed via Phabricator it updates the patch attached to the
review. I downloaded the raw patch from Phabricator, applied it, and repeated
my mistake from r345704 by accident mixing content from D19732 and D19738.

For my own personal sanity, I will try not to mix reviews like this in the
future.

MFC after: 1 month
MFC with: r345706
Approved by: emaste (mentor, implicit)

Standardize `-std=c++* as `CXXSTD`

CXXSTD was added as the C++ analogue to CSTD.

CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.

This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.

As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.

Notes:

This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.

Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:

Before this commit:
```
CXXFLAGS+= -std=c++14
```

After this commit:
```
CXXSTD= c++14
```

Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
MFC with: r345203, r345704, r345705
Relnotes: yes
Tested with: make tinderbox
Differential Revision: https://reviews.freebsd.org/D19732

Revert r345704

I accidentally committed code from two reviews. I will reintroduce the code to
bsd.progs.mk as part of a separate commit from r345704.

Approved by: emaste (mentor, implicit)
MFC after: 2 months
MFC with: r345704

CXXSTD is the C++ analogue to CSTD.

CXXSTD defaults to `-std=c++11` with supporting compilers; `-std=gnu++98`,
otherwise for older versions of g++.

This change standardizes the CXXSTD variable, originally added to
googletest.test.inc.mk as part of r345203.

As part of this effort, convert all `CXXFLAGS+= -std=*` calls to use `CXXSTD`.

Notes:

This value is not sanity checked in bsd.sys.mk, however, given the two
most used C++ compilers on FreeBSD (clang++ and g++) support both modes, it is
likely to work with both toolchains. This method will be refined in the future
to support more variants of C++, as not all versions of clang++ and g++ (for
instance) support C++14, C++17, etc.

Any manual appending of `-std=*` to `CXXFLAGS` should be replaced with CXXSTD.
Example:

Before this commit:
```
CXXFLAGS+= -std=c++14
```

After this commit:
```
CXXSTD= c++14
```

Reviewed by: asomers
Approved by: emaste (mentor)
MFC after: 1 month
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D19732

Spam CXXFLAGS with `-I${DESTDIR}/usr/include/private`, instead of GTEST_CXXFLAGS

This makes it easier for googletest users to leverage googletest, instead of
forcing them to plug GTEST_CXXFLAGS into CXXFLAGS manually (resulting in
unnecessary duplication).

I will be following this up with a more proper fix in src.libnames.mk, as
src.libnames.mk should be automatically adding this directory to
CFLAGS/CXXFLAGS when private libraries are referenced. Not doing so can result
in mismatches between base-provided private library's and ports-provided
library's headers.

While here, tweak the comment to clarify what the intent is behind spamming
CXXFLAGS.

MFC after: 5 weeks
MFC with: r345203
Reported by: asomers
Reviewed by: asomers
Approved by: emaste (mentor)
Differential Revision: https://reviews.freebsd.org/D19731

Adjust code based on comments from @asomers in D19551

Remove redundant CXXFLAGS and fix constant names

- Specifying -std=c++11 and -frtti tweaks those flags with clang/gcc.
- The constants are prefixed with `GTEST_`, not `GTESTS_`.

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

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

Use gmock/gtest headers when PRIVATELIB is defined

The move to /usr/include/private prefixed paths seems to require a bit more
effort in order to compile programs.

Install the headers to /usr/include/private/g{mock,test}/... and automatically
include /usr/include/private in GTESTS_CXXFLAGS to make compilation seamless. I
will work on the more global problem later with @bdrewery.

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