libass-dev software package provides development files for libass, you can install in your Ubuntu 12.04 LTS (Precise Pangolin) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libass-dev
libass-dev is installed in your system.
Make ensure the libass-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libass-dev *
You will get with libass-dev package name, version, architecture and description in a table
| Distro | Ubuntu 12 04 lts precise pangolin |
| Section | Library development |
| Package | libass-dev |
| Version | 0.10.0-3+deb7u1build0.12.04.1 |
| Description | development files for libass |
| Sub Section | libdevel |