Remove jruby from kokoro tests

Declare 'google' namespace when importing Python protobuf via Bazel

Add kokoro configs for bazel build.

In old generated code, the constructor of message doesn't provide a
default null to parent's constructor. Previously, in c extesnion, this
case was not handled.

* uses namespaces for nested messages and enums

* fixes namespaces for PHP dist

* fixes namespace for Descriptors, adds Cardinality and Kind

* fixes nested namespaces for reserved words and adds tests

* adds tests and generator fix for php class prefixes

* fixes escaping of protobuf packages, enum comments, misc others

* nice refactor of generated code

* adds class files for backwards compatibility

* simplifies code with templates

* adds compatibility files to makefile

* cleanup of generator and fixes nested namespace bug

* regenerates proto types

* remove internal BC classes

* adds deprecated warning, adds methods back

* simplifies if statement

* fixes dist files

* addresses review comments

* adds back TYPE_URL_PREFIX constant

* adds @deprecated to old nested class files

* skips tests which require a separate process when protobuf.so is enabled

* Adds tests for legacy nested classes that do not require separate processes to test

* uses legacy names for GPBUtil message check

* adds block for IDE @deprecated message

* Namespace for nested message/enum in c extension

* Remove unused code

* PHP array constructors for protobuf messages

* removes Descriptor from error message

* allows mergeFrom to accept an array

* only use initWithDescriptor if instanceof MapEntry

* adds doc comments

* removes ability for constructors to take arrays for submessages

* Revert "allows mergeFrom to accept an array"

This reverts commit b7b72182d561634af12c5c5c56a7cda3b33241f9.

* makes mergeFromArray protected and fixes mergeFrom whitespace

* Separates merging from JSON and merging from PHP array

* removes well-known types and json keys from array construction

* Addresses PR review comments

* cleans up tests

* fixes exception messages

Fix syntax error in BUILD file

`python/google/__init__.py` declares the top-level 'google' namespace so that
`google.protobuf` can be imported alongside other Google Python modules like
`google.auth`.

This works well when installing protobuf via Pip, but the Bazel `//:python_srcs`
rule doesn't include this file in its `srcs`. Bazel implicitly creates an empty
`google/__init__.py`, which does *not* set up a namespace. The result is that
consuming Python protobuf via Bazel breaks all other Google Python libraries.

This fixes #4658.

Add missing ruby/tests/test_ruby_package.proto

* CMake: Add comment for CMP0048

* CMake: osx use @rpath/ as target's install name (CMP0042)

On MacoS library should use @rpath/ as prefix path instead of absolute build path
e.g. otool -L libprotobuf.dylib
libprotobuf.dylib:
  @rpath/libprotobuf.dylib (...)
  ...

* CMake: add rpath to target for LINUX and APPLE

Fix python benchmark build

Windows: expand wildcard arguments

Fixes https://github.com/google/protobuf/issues/3957

Fix java benchmark bug, fix python lib cache

Updated PHP generated code for timestamp.proto

* Adopt ruby_package in ruby generated code.

* Add test for ruby_package

* rewrite int128 long divison to avoid stackoverflow hit

Protobuf was showing Stackoverflow hits in the code base, primarily code written to calculate long division. This code was copied from a stackoverflow post, which means it would be licensed under CC BY-SA 3.0. Due to this license, IBM Legal did not want to include this OSS in our products and advised us to re-write this particular piece of code to avoid the license restriction. We have re-written the code for our own distribution, and are willing to merge it into the main code base for others who want to avoid the stackoverflow license issues to benefit as well.

cmake: protobuf_generate fix GENERATE_EXTENSIONS, fix DEPENDS, add PROTOC_OUT_DIR

Fix 4615

The problem is that sched_yield is available on the target, but configure.ac is asking to build
a host binary using the AC_SEARCH_LIBS macro.  It can't configure for Android, since sched_yield isn't
available on the host.

Fix undefined behavior in hash function.

Fix issue with version.rc

Fix appveyor documentation

Fix python install, cat java error log for kokoro build

* Adopt php_metadata_namespace in php code generator

The php_metadata_namespace is corresponded to the relative directory of
the metadata file. e.g., previously, the metadata file of foo.proto was
GPBMetadata/Foo.php. If the php_metadata_namespace is "Metadata\\Bar",
the metadata file will be Metadata/Bar/Foo.php.

* Handle empty php_metadata_namespace

Signed integer overflow creates undefined behavior that may lead to unpredictable fails on different platforms.
One known example of the hardware where this code did fail is Apple A6 (32-bit Apple Swift CPU)

16777619, 16777499 - two prime numbers that typically used to get better dispersion.