heroku/heroku-buildpack-nodejs — pull request #30 by davidjrice (2013-02-26 03:15:58+00:00)
Title: Preserve ENV vars CPATH and CPPPATH (composable buildpacks)

Not overriding these variables entirely in the nodejs buildpack allows for it to be easily composable with others that provide dependencies not specifiable in an npm `package.json` using the **heroku-buildpack-multi** without having to hack the nodejs buildpack itself.