Some enhancements

[eugeniodilo]

Hi
I found your program ... very nice !
I added some changes and sent you the new cobol source that can be compiled with GnuCOBOL.
It calls a GC01BOX utitlity ... you can find the COBOL and COPY source at
https://sourceforge.net/p/gnucobol/contrib/HEAD/tree/trunk/tools/TUI-TOOLS/

[GitMensch]

See https://github.com/eugeniodilo/snek/blob/patch-1/snake.cbl for the changes.

Note @eugeniodilo: if the box program is not available at the first call it is unreasonable to call it again (so maybe add a variable to check).
Maybe have that completely optional and "draw" with plain single ascii characters in a small section which you PERFORM and DISPLAY AT for the boxes (then you'd also have to replace the COPY statement with the content) - or always do this to not introduce any dependency?