Google::Protobuf::Struct can access a missing key (#3846)

Missing symbol exports for Windows DLL

Remove write-strings warning from COPTs

Add wsrpc

This should fix https://github.com/google/protobuf/issues/4717

This fixes issue #2610.

This was originally fixed in a101fa52 , but got
reverted by d36c0c53

Fix to allow a compilation under mips big endian with gcc

Internal convert file was broken. Change the capsule to the correct name

This change reduces the excessive warnings when compiling C++ protobufs like "external/protobuf_archive/python/google/protobuf/pyext/message.cc:2629:1: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]"

The __MIPSEL__ is mips little endian, specific and we needed
to compile for a big endian mips target that also happened
to be a mips64, so replaced the __MIPSEL__ with a __mip__
which should preserve the build on little endian and allow a
build for a big endian setup.

	$ echo | mips64-linux-gcc -E -dM -
	... snip snip ...
	#define __mips__ 1
	#define __MIPSEB__ 1
Signed-off-by: Charles Hardin <ckhardin@gmail.com>

* Add -Og to no-warning-test

* Initialize value

* Implement PrintFieldName in CompactRepeatedFieldPrinter to prevent Woverloaded-virtual

* Update generated code

* This allows for ruby code to catch and handle Protobuf
    TypeErrors separately from the standard Ruby TypeError

  * Maintains backwards compatibility by having the new
    Google::Protobuf::TypeError inherit from the base
    TypeError. Any code that was catching TypeError should
    continue to work.

Removed forward declaration of MemBlock class

Removed forward declaration of MemBlock class.

Declaration is in conflict with declaration `::strings::MemBlock`

Merge 3.6.x branch into master

* Remove protoc conditional properties

* Fix duplicate brace

the testMessageSetNullFail function was declared twice.
So I renamed one to testMessageSetNullFailMap

Remove the executable bit from several source code files

Fixed protobuf_generate output definition

Added `-y` flag to `sudo apt-get` command.

Add "override" keyword for overridden virtual functions

Add guards against bswap_XX redefnitions

* 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

This change helps both humans and linters to understand the unusual method of instantiating this global variable.

This potentially avoids compiler warnings.

update ScalaPB url

Use versions module from Skylib for version checking 

* Add files to build ruby artifact for mac on kokoro

* Move ruby specific stuff to ruby dir

Fix parameters declaration

protostream_objectwriter: fix bug when Any is directly embedded in a …

protostream_objectsource: preserve print options across Any.

* Added props to C# tools

* Add targets file to makefile.am