libxfce4util-dev software package provides Development files for libxfce4util6, 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 libxfce4util-dev
libxfce4util-dev is installed in your system.
Make ensure the libxfce4util-dev package were installed using the commands given below,
$ sudo dpkg-query -l | grep libxfce4util-dev *
You will get with libxfce4util-dev package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Library development |
| Package | libxfce4util-dev |
| Version | 4.10.1-1ubuntu1 |
| Description | Development files for libxfce4util6 |
| Sub Section | libdevel |