With a few minimal changes, mainly the removal of a pseudo-terminal window
(every modern OS has a real terminal available now) and the change of the
construction copy(str, 1, 1) to str[1] as a way to get the first character
of a string, the Think Pascal source files by Jos Kunst compile successfully
using the Free Pascal compiler (version 3.2.2). See https://www.freepascal.org/.
On Mac OS X 12.6.2 on an Intel Mac mini I used the following command:
$
To create an executable called 'dsg'.