LOADACS
From ZDoom Wiki
LOADACS is a lump which supports automatically loading ACS objects (even for Doom-format maps).
To use it, compile the ACS files as ordinary libraries placed between A_START/A_END markers.
Then outside the markers, create a lump called LOADACS. This is just a plain text lump that lists all the libraries you want to autoload with every map. You can do this with as many libraries as you want, and LOADACS lumps are also cummulative.
NB: This is often referred to as Global ACS, though this is not, and has never been, its true name.
Example
Here's an example of using LOADACS to include two compiled ACS lumps which should be between A_START/A_END markers.
myscript usethis
The scripts in both these lumps will be used in every map.
