libqt5x11extras5-dev software package provides Qt 5 X11 extras development files, 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 libqt5x11extras5-dev
libqt5x11extras5-dev is installed in your system.
Make ensure the libqt5x11extras5-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libqt5x11extras5-dev *
You will get with libqt5x11extras5-dev package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Library development |
| Package | libqt5x11extras5-dev |
| Version | 5.2.1-1 |
| Description | Qt 5 X11 extras development files |
| Sub Section | libdevel |