libpq-dev software package provides header files for libpq5 (PostgreSQL library), 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 libpq-dev
libpq-dev is installed in your system.
Make ensure the libpq-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libpq-dev *
You will get with libpq-dev package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Library development |
| Package | libpq-dev |
| Version | 9.3.14-0ubuntu0.14.04 [amd64, |
| Description | header files for libpq5 (PostgreSQL library) |
| Sub Section | libdevel |