Fix iOS cc_library build for protobuf.

CodedInputStream::SetTotalBytesLimit description fix

fix implicit fallthrough in gcc 7

Integrate google internal changes for the up coming 3.5 release.

fixes issue #3750

Add the proto-lens Haskell library to the 3rd party doc.

protobuf_generate: create include path only for proto files

Add GopherJS protobuf and gRPC links

Fix: Truncated Message due to "TypeError: unhashable type: 'bytearray'"

Remove C++11 only usages in io_win32 tests.

Fix undefined memory management found by Clang's sanitizers.

See https://github.com/google/protobuf/issues/3752 for context.

The SDK and os versions were hard coded.  Archs were mixed up.
Because of this,  Was getting errors with latest SDK:
clang: warning: no such sysroot directory: '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.2.sdk/' [-Wmissing-sysroot]
clang: warning: no such sysroot directory: '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.2.sdk/' [-Wmissing-sysroot]
clang: warning: no such sysroot directory: '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.2.sdk/' [-Wmissing-sysroot]
In file included from external/com_google_protobuf/src/google/protobuf/io/printer.cc:35:
In file included from external/com_google_protobuf/src/google/protobuf/io/printer.h:40:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:470:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:171:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:638:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cstring:61:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string.h:61:15: fatal error: 'string.h' file not found
              ^~~~~~~~~~
              1 error generated.

Currently none of these are needed when using bazel with https://github.com/bazelbuild/rules_apple.
-target arm64-apple-ios is passed properly to clang.  So -arch armv7 etc are not needed.
OS_IOS is not used anywhere.
Sources have:  GOOGLE_PROTOBUF_NO_THREADLOCAL defined in src/google/protobuf/stubs/platform_macros.h for iOS.  So __thread= is not needed.  In fact now that bazel is using C++11 by default,  __thread should ideally be moved to thread_local.
-miphoneos-version-min is passed by rules_apple.

fixes #3700

In protobuf-module.cmake: in addition to checking for release or debug
variants of protoc's location we should also check the configuration "noconfig".

Move namespace closing brace inside the header guard block

Merge3.4

Don't pass -lpthread and -lm on Windows

These flags are ignored by cl.exe and have no effect, but add noise to the build logs.

* Reserve unknown fields in upb
1) For decoding, an unknownfields will be lazily created on message,
which contains bytes of unknown fields.
2) For encoding, if the unknownfields is present on message, all bytes
contained in it will be serialized.

* Register the function to encode unknown field at decode time.

* Remove upb_handlers_setaddunknown

* Use upb_sink_putunknown in decoder

* Remove upb_pb_encoder_encode_unknown

* Do not expose encode_unknown

* Implement reserve unknown field in php Implement.

* Make buffer private to CodedInputStream

* Add well known types to php runtime.

* Fix php7.0 tests

* No longer generate empty.proto in test as it has been included in
runtime.

* Fix zts build

* Clean code

* Rename g_p_b_empty to empty.

* Don't generate code for empty.proto in compatibility test

* Fix 32-bit

* Fix mac build

* Fix Makefile.am to add new files

* Fix ruby segment fault

1) rb_ary_new cannot be called during allocate function. During allocate
fucntion, the containing object hasn't been marked and rb_ary_new may
invoke gc to collect containing object.
2) The global map should be marked before allocating it. Otherwise it
may be garbage collected.

* Add test

* Remove commented code

* Fix grammer error

Objc increase test coverage