LibPD and externals

"When dynamic loading is not available, clients can have externals compiled into them and initialize them by calling the setup function after calling the libpd_init function."
- https://github.com/libpd/libpd/wiki/misc

"All Pd assets (patches, audio files, text files, externals) must be placed in Assets > StreamingAssets > PdAssets. libpd will not be able to find any of the resources in a build if the assets are placed in another folder."
- http://twobigears.com/labs/unity-and-libpd/