gnustep-back0.20 software package provides GNUstep GUI Backend, you can install in your Debian 7 (Wheezy) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gnustep-back0.20
gnustep-back0.20 is installed in your system.
Make ensure the gnustep-back0.20 package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnustep-back0.20 *
You will get with gnustep-back0.20 package name, version, architecture and description in a table
| Distro | Debian 7 wheezy |
| Section | Libraries |
| Package | gnustep-back0.20 |
| Version | 0.20.1-2.1 |
| Description | GNUstep GUI Backend |
| Sub Section | libs |