The source code can be obtained at Github.com.
From the repository:
"This repository contains the source code for Hovertank 3-D. The source code is designed for Borland C++ 2.0, but compiled fine with Borland C++ 3.1 at the time of this release. It is released under the GNU GPLv2. Please see COPYING for license details. This release does not affect the game data files. You will need to legally acquire the game data in order to use the exe built from this source code. "