Cannot run on Linux: Required engine files not found. Run `make` in the mod directory to fetch and build the required files, then try again.

[fusion809]

When I run the command:

./launch-game.sh

after building this mod with make, I receive the error:

Required engine files not found.
Run `make` in the mod directory to fetch and build the required files, then try again.

(Platform is Arch Linux).

At least part of the issue is that building this mod no longer creates an OpenRA.exe file, instead an OpenRA.dll file is generated in engine/bin. But I have found that modifying the launch-game.sh file so that it uses OpenRA.dll instead of OpenRA.exe does not fix this error.