ASTAP is written in Object Pascal and compiled with the Free Pascal Compiler using Lazarus the open source cross platform IDE. 

For the Windows use the astap.lpi project file.
For the Mac use the astap_mac.lpi project file.
For Linux use the astap_linux.lpi project file.
For the command-line version use /command-line_version/astap_command_line.lpi

{Copyright (C) 2017-2021 by Han Kleijn, www.hnsky.org
 email: han.k.. at...hnsky.org

{This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
}