mwotton/heroku-buildpack-haskell — pull request #1 by timjb (2012-11-12 20:06:07+00:00)
Title: Add `heroku-pre-install` hook

I've got a project that depends on the `regex-pcre` package, which in turn depends on the `pcre` C library. Since Heroku doesn't have that library installed, I have to write a script that downloads and builds the C library and installs `regex-pcre` with `--extra-lib-dirs`. This commit allows me to do that by including a script named `heroku-pre-install` in my Haskell Heroku app that gets executed before `cabal install`.