We have long published LAC precompiled for the Pi4b and Pi400.
Before running the precompiled executable on that platform, it's
necessary to install the following free software libraries from the
"Add / Remove Software" facility according to the usual pattern:
1 of 3: freeglut3-2.8.1-3 or later
2 of 3: libsdl1.2debian-1.2.15+dfsg2-6~deb10u1 or later
3 of 3: libsdl-mixer1.2-1.2.12-15 or later.
Once you've installed those libraries and downloaded LAC's free archive
distribution for Raspberry Pi 4b, you can just sudo/run the
"install.sh" shell script (included with the download archive) to
install it.