more information is probably always welcome 😀
broke is a bit uninformative...

Sorry about that, I should have said that the game won't start. Backing out that change does fix it so I assume it just needs a little rework in order to keep the intent of the original change. The game tries to change directories to "c:". Before the change this would return without error, after the change this returns path not found.

Trying to change the current directory using a "C:" path spec with INT 21/3B returns error 3 (path not found) in real DOS, so revision 3616 (along with revision 3659) is producing the intended DOS-compatible behavior.

Perhaps the GoG version of the game is in some way relying on the previous, incompatible behavior; however, I'm unable to reproduce any problem with the original cdrom version of LBA2 -- it starts up fine in 0.74 and SVN with default settings when installed normally.

Looks like the bug is with the game. It was not meant to be installed in the root directory. GOG mounts the game in the root directory, but the older version of Dosbox they use lets them get away with it.

I just tested the game by mounting 1 directory above the game so that I would have to CD into the game directory and that worked fine.