gnat-4.9-base software package provides GNU Ada compiler (common files), 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 gnat-4.9-base
gnat-4.9-base is installed in your system.
Make ensure the gnat-4.9-base package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnat-4.9-base *
You will get with gnat-4.9-base package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Libraries |
| Package | gnat-4.9-base |
| Version | 4.9.2-1 |
| Description | GNU Ada compiler (common files) |
| Sub Section | libs |