This is a mod for minecraft: pi edition reborn that expands the creative inventory so that you have access to all items.
To use this mod you will need to download the shared library and place it in the mods folder of minecraft: pi edition, to do this download libbci.so and run
mv ~/Downloads/libbci.so /opt/minecraft-pi-reborn-client/mods/libbci.so
Then all you need to do is run minecraft: pi edition with the Expand Creative Inventory mod activated.
To compile your own version of it you will need the libreborn folder and the creative.cpp file, then once you finish editing creative.cpp, you run:
arm-linux-gnueabihf-g++ -shared -o libbci.so creative.cpp -DREBORN_HAS_COMPILED_CODE
This will compile a version of libbci.so with your changes.