libghc-fgl-dev software package provides Haskell graph library for GHC, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libghc-fgl-dev
libghc-fgl-dev is installed in your system.
Make ensure the libghc-fgl-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libghc-fgl-dev *
You will get with libghc-fgl-dev package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Haskell |
| Package | libghc-fgl-dev |
| Version | 5.5.0.1-1+b1 [s390x], 5.5.0.1- |
| Description | Haskell graph library for GHC |
| Sub Section | Haskell |