libgnatvsn4.9 software package provides GNU Ada compiler selected components (shared library), 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 libgnatvsn4.9
libgnatvsn4.9 is installed in your system.
Make ensure the libgnatvsn4.9 package were installed using the commands given below,
$ sudo dpkg-query -l | grep libgnatvsn4.9 *
You will get with libgnatvsn4.9 package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Libraries |
| Package | libgnatvsn4.9 |
| Version | 4.9.2-1 |
| Description | GNU Ada compiler selected components (shared library) |
| Sub Section | libs |