Google protobuf for Android NDK

This builds a static library to use protobuf with C++ on android.

This is based on protobuf-2.6.1 and it boils down to :

• Copying the minimal set of .cc files to build the library (without tests)
• Write a config.h and Android.mk that work on android

The example directory contains an example protobuf that can be compiled & linked by NDK to check that the linker has all the dependencies:

cd example

./build.sh