* Use set -ex
* Use -std=c++14 so -latomic can be found

* Fix python release build.
* Separate config.sh by platform
* Use KOKORO_JOR_NAME to determine the BUILD_COMMIT.
* Use -std=c++14 on MacOS so -latomic can be used.

* Add ruby 2.6 gem build for linux

* Add docker hub organization

* Add ruby2.6 in cross compile targets

* Fix tests

* Check mac version

* No need to install php in preparation for mac

* Add kokoro build for python source package

* Use libc++ for xcode 10 (#5303)

The xcode 10 removes the deprecated libstdc++ library. We could set
"MACOSX_DEPLOYMENT_TARGET" to "10.9" to use libc++ instead.

* Add python 3.7 build

* Add build for python 3.7 on linux and windows

* Remove unused source build

* Add comment

* Fix $MACOSX_DEPLOYMENT_TARGET mismatch

* Fix MACOSX_DEPLOYMENT_TARGET mismatch

* Add missing import for sysconfig

* Add missing imports

* Add kokoro config for building python wheels on windows

* Move script to root

* Debug

* Debug

* Change working directory

* Add msbuild to path

* Debug

* Fix python dir name

* Debug

* Move artifacts to targeted directory

* Update artifact directory

* Debug

* Debug

* Automatic generation of version

* Reduce file numbers

* Add config for building python wheel on mac

* Specify os name

* Clean up venv

* Debug

* Recover old path

* Add config for building python wheel

* Update submodules

* Fix setup.py to use c++11

* Fix syntax error

* Fix syntax error

* Add dir for artifact

* Update artifact dirctory

* Remove python 3.3

* Clean up virtual env

* Clean up env

* Test environment

* Test env variable

* Automatic update version number

* Remove dependency on python-wheel branch

This reverts commit c02346c72aafd1826b0397dbbce4ce04bf252f50.

This was fairly straightforward using the existing build-protoc.sh
script. The only problem I ran into was that the x86 Docker builds
create output directories owned by root, which caused some permission
issues. Fortunately it was easy to get around that just by doing those
Docker builds last.

* upgrade dotnet SDK to 2.1.3 on kokoro linux

* Install rake compiler

* Add kokoro config to build ruby gem on linux

* Rename from linix to linux

* Fix prepare_build.sh name

* Clean up

* Install bundler

* Install bundler

* Use c99 in order to build gem on mingw-32 on ruby 2.0.0

See https://github.com/rake-compiler/rake-compiler-dock/issues/4

* Move c99 config to extcofig.rb

* Add files to build ruby artifact for mac on kokoro

* Move ruby specific stuff to ruby dir

This configuration builds both 32-bit and 64-bit binaries for Mac OS X.
One thing I had to change was to increase our minimum supported version
for 10.7 to 10.9, because 10.9 (Mavericks) appears to be the earliest
version supporting C++11.

This should make it easy to automatically build 32-bit and 64-bit
Windows protoc binaries.