Emscripten port of Google's Protobuf library.
cd [2.6.1|3.1.0]
sh autogen.sh
emconfigure ./configure
emmake Make
This will generate a dynamic library in src/.libs/ called libprotobuf.$(VERSION).[so|dylib].
Though the suffix suggests that this is a regular dylib, it contains emscripten bytecode.
Change the suffix to .bc and you'll be able to link it into your emscripten project.
The protoc compiler will not be build but any code generate by the standard protoc is compatible
with emscripten.
Protobuf: Original license
Patches: Public Domain