libgdm-dev software package provides Next generation GNOME Display Manager (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 libgdm-dev
libgdm-dev is installed in your system.
Make ensure the libgdm-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libgdm-dev *
You will get with libgdm-dev package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Library development |
| Package | libgdm-dev |
| Version | 3.10.0.1-0ubuntu3 |
| Description | Next generation GNOME Display Manager (development files) |
| Sub Section | libdevel |