libxss-dev software package provides X11 Screen Saver extension library (development headers), you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libxss-dev
libxss-dev is installed in your system.
Make ensure the libxss-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libxss-dev *
You will get with libxss-dev package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Library development |
| Package | libxss-dev |
| Version | 1:1.2.2-1 |
| Description | X11 Screen Saver extension library (development headers) |
| Sub Section | libdevel |