Thanks for your help @ChristopheF !
I succeded in installing and running CSBuild on macOS using the wine-wrapper Whiskey (
https://getwhisky.app). When loading my DOS savegame it displays multiple error messages, some of them a little funny ("unnatural"):
"Number of Levels > 64"
"The databases in the savegame file appear damaged"
"Error reading big-endian...will try little-endian"
"Illegal object at 0(-4,00) Object value = 0xfffe"
"ONE OR MORE OBJECTS HAVE BEEN DELETED
FROM THE DUNGEON BECAUSE THEY ARE LOCATED
IN MORE THAN ONE PLACE IN THE DUNGEON AT
THE SAME TIME. THIS IS NOT ONLY UNNATURAL
IT CAN CAUSE BIG PROBLEMS.
IF YOU REALLY WANT THIS TO HAPPEN, SELECT
Edit|Options|Allow Cloned Objects BEFORE
YOU LOAD YOUR DESIGN TO BE EDITED.
Object 1784 at 0(-4,00) is in more than one place.
Object 1803 at 0(-4,00) is in more than one place.
Object 1835 at 0(-4,00) is in more than one place."
... but then after clicking "Cancel" it loads all levels without problems.
I found the Hardcleave in level 9 where it belongs! Silly me, I thought that I took it, but I didn't
Thanks again!