You can always quit the program at once using Ctrl + Alt + X, or press the
quit button in the main menu (which on the other hand doesn't have text yet).
This requires the libraries
Gusgame (link)
GusGui (link)
Allegro5 (link)
For cppcheck, use the command
cppcheck --enable=all --suppressions-list=../cppcheck-suppressions.txt --check-config -I/usr/include/lua5.3 -I/home/gusnan/kod/puzzle/puzzle/src -I/usr/local/include -I/usr/include/ -I/usr/include/c++/10/ -I/usr/include/x86_64-linux-gnu/c++/10/ ../src
(not mentioned in the cppcheck-suppressions.txt file, since it cannot be done with comments and ruins the syntax, and makes the suppresions file not usable).