Not compatible with latest protobuf-c

[quark-zju]

The latest protobuf-c https://github.com/protobuf-c/protobuf-c/blob/master/protobuf-c/protobuf-c.h has changed its interface (for example PROTOBUF_C_BEGIN_DECLS is renamed to PROTOBUF_C__BEGIN_DECLS and there are other changes). This leads to pytrace complication failure on distributions shipping newer protobuf-c such as Arch Linux and Debian 8.

Can we consider include a working protobuf-c souce code to solve it?

[alonho]

Sounds reasonable. Are you interested in submitting a PR?

[alonho]

Pushed a fix to work with latest protobuf. The optimal solution would be to re-generate the header files using protoc (the protobuff compiler) when compiling the extension. It's easier than bundling entire protobuf and the API for the application hardly ever changes. Leaving this open until I provide the better solution