$ sudo apt-get update
$ sudo apt-get install libgd-dbg 

libgd-dbg is installed in your system.

Make ensure the libgd-dbg package were installed using the commands given below,

$ sudo dpkg-query -l | grep libgd-dbg *

You will get with libgd-dbg package name, version, architecture and description in a table

libgd-dbg package basic information: