Protobuf library should upgrade to protobuf 3.3

[reyoung]

The current release of protobuf is 3.3.2, but Paddle is using protobuf 3.1.0. In protobuf 3.1.0, there are several bugs which affect our code:

• In Protobuf 3.1.0, map in protobuf cannot be compiled by GCC with -Wextra.
  • The protobuf issue is g++ error with -Wextra when compiling protobuf protocolbuffers/protobuf#2425.
  • In our attribute design, map is used to associate from attribute name to value.
• Protobuf 3.1.0 uses a deprecated API on MacOS.
  • The protobuf issue is Deprecated atomic function invocation on MacOS Sierra protocolbuffers/protobuf#2182
  • Our issue is The protobuf 3.1.0 cause a warning in MacOS building #1936.

[reyoung]

@wangkuiyi @gangliao Should we upgrade our protobuf library? If we should, I could give a PR tomorrow.

[gangliao]

@Xreki I don't have the environment to build the protobuf 3.3.2 on ARM, @Xreki Can you please build this version? Is it feasible to upgrade protobuf?

[Xreki]

I have tried to build the newest protobuf before and met some problem. In the building process of the newest version, there is a need to generate a binary file and run the binary file.
In cmake/libprotoc.cmake

add_executable(js_embed ${protobuf_source_dir}/src/google/protobuf/compiler/js/embed.cc)
add_custom_command(
  OUTPUT ${protobuf_source_dir}/src/google/protobuf/compiler/js/well_known_types_embed.cc
  DEPENDS js_embed ${js_well_known_types_sources}
  COMMAND js_embed ${js_well_known_types_sources} > ${protobuf_source_dir}/src/google/protobuf/compiler/js/well_known_types_embed.cc
)

Simple command make was used, thus all the targets of Protobuf will be made. I will try another detailed command like make libprotobuf to not build protoc.

[reyoung]

This issue is blocked by Protobuf's cmake. We cannot upgrade our protobuf from 3.1 to 3.3 because, in 3.2, cmake cannot build a cross-compile protobuf.

The PRs are added and not merged.

• CMake: Android crosscompiling protocolbuffers/protobuf#2998
• changes for CMake to support cross-compilation protocolbuffers/protobuf#2980

[qingqing01]

The protocolbuffers/protobuf#3878 fixed cross-compiling for android.