This is a Heroku buildpack that allows you to install swig which is a system dependency needed for many libraries to function correctly. E.g. M2Crypto.
Use this in conjunction with the Heroku buildpack: multi to use your buildpack of choice once swig is installed. E.g. Heroku Python buildback.
To use this buildpack you'll first need to set the multi buildpack as your custom buildpack:
$ heroku buildpacks:set https://github.com/heroku/heroku-buildpack-multi.git
From here you will need to create a .buildpacks file which contains this buildpack and then the other buildpacks which will trigger dependencies on swig.
$ cat .buildpacks
https://github.com/jamarparris/heroku-buildpack-swig
https://github.com/heroku/heroku-buildpack-python
MIT