Google.Protobuf should target net45 (and not net451)

internal descriptor.proto

Add mising cmake files in dist

Remove pre-installed softwares

Make distcheck aware of test proto files.

Disable death tests on windows

Also remove cord related code

Use message name as defined in php runtime.

Merge pull request #3535 from drivehappy/clang_warn_cleanup

Merge pull request #3494 from drivehappy/clang_warning_macro

Fixing -Wexpansion-to-defined Clang warning

Fixing unused parameter warnings under Clang.

Remove C++11 features in io_win32.cc

- Use scoped_array instead of unique_ptr.
- Do not use string::front() and string::back()

Bump gemspec again

Prefer system distributed binaries/libraries.

Bump gem version for the next upload

Update testpypi URLs

It seems like the image has a /usr/local/bin/autoconf installed, which
doesn't recognize/work with the yum installed libtools. Putting
distributed binaries/libraries first solves the problem

The old one is deprecated and no longer working.

Add std::forward and std::move autoconf check

Static link pthread for mingw64 protoc and enable cross compile