For reasons I don't follow, when passing CXXFLAGS to configure, the build
ends up breaking because something along the way fails to detect C++11
support within the third_party/googletest part of the build.

* Bump target frameworks from netcoreapp1.0 to netcoreapp2.2.
Move global.json up to root of repo, change SDK ver to 2.2.100
Change .net core sdk in dockerfile for kokoro to ver 2.2.100

* Re-add curl install

* Change all exe target to 2.1

* Fix incorrect versions in global.json and Dockerfile

* Downgrade version to 2.1 to match exe targets

* introduce separate testing Dockerfile for C#

* revert changes to the shared Dockerfile

* use netcoreapp2.1 for C# conformance tests

* use language specific dockerfile for testing C#

* Edit compatibility tests script to use parameters instead of file copies

* install dotnet SDK on windows before running the tests

* update csharp_EXTRA_DIST

* Improve C# serialization performance of repeated fields for primitives.

* Changes based on feedback.

* Change compatibility tests to chec float, bool and double are fixed

* Changes based on feedback.

* In the compute methods use the newly created constants

Recently dependency to error_prone_annotations was added to the code,
but only Maven build tool chain was updated.

Closes #5795.

* Fix ruby continuous tests

* Fix compatibility test

* Add link to continuous test badges

* Add badge for dist_install

* Add a new test for verifying that the dist package can be installed.

* Some fixes to make the code work in google3.

* Removed plugin.h.

* Some more fixes to be namespace-independent.

* More fixes for namespace independence.

* A few final fixes.

* Another fix (hide ToUpper from Copybara).

* Fix for charp_unittest.

This change introduces a CriticalSectionLock class as a lightweight replacement for std::mutex on Windows platforms. std::mutex does not work on Windows XP SP2 with the latest VC++ libraries, because it utilizes the Concurrency Runtime that uses ::GetLogicalProcessorInformation which is only supported on Windows XP SP3 and above.

This reverts commit 37581380.

* Down integrate to github

Merge 3.7.x to master

Replaced shortn URL with intended URL.

* Revert "Revert "Fix Ruby module name generation when the ruby_package option is used (#5735)""

This reverts commit bb211e85.

* add new files to Makefile.am

* add frozen checks

* Use rb_check_frozen

* Correct assertion on frozen error message

The second argument for the method assert_raise is the message
to show when the assertion fails. It does not check the error
object's message.
Add an additional assertion that does check the error's message.

* do frozen check first

* example with extra enum method

* update expected test output

* slight simplification

* add test for generated enum helpers

* move const helpers to c extension

* more explicit test

* more explicit test

* indent

* add foo test

* add check for _const suffix

Updating Iterators to be compatible with C++17 in MSVC

* Update version number to 3.7.0

* Add php/releash.sh to Makefile.am

* Make cpp_distcheck exit on fail

Revert "Fix Ruby module name generation when the ruby_package option is used"

This reverts commit 9638dcc3.

* fix module name generation and add tests

* fix existing tests

* support both package name styles

* add check for overflow

* de-nestify

* break long lines

* let repeated fields push arrays

* add varargs push

* better test

* Fix construction of messages using the C++ Python implementation when a map field is passed from one message to another.

* Add a test on message map field construction

* python 3 support

* review comments

* add test

* Collapse code into one

Added Optional GRPC library to third party docs

down integration from internal

Cherry-pick fixing for mac tests after kokoro updates