This is a custom version of squirrel (based on elmer's elusive squirrel-2021-12-03.zip release).
It has been slightly modified to run mostly from a subdirectory.
I made it to minimize the clutter in my workspace because Squirrels 69,420 files and directories triggers my OCD.

It is unauthorized. Do not bother Aetherbyte if it doesn't work.
Tested and working with HuC (v4.00-97bc654-dirty, 2022-09-03)

Install by copying the files to the root directory of your project.
Keep sound.inc and sound.asm in the root directory. Alternatively you can edit huc's startup.asm to move them elsewhere...
Keep mml2pce.exe in your project root directory too. It will generate the required sngInit.c file (also in the project root).
Put your MML files in the "mml" directory" and convert them with mml2pce, e.g. mml2pce.exe mml/multitrack.mml

#include "mml/squirrel/squirrel.h" in your project and then use squirrel normally e.g. psgPlay(0);

Look at and/or try compiling the example.c file ("huc example.c")
Delete this README.TXT and the example.c/.s/.lst/.sym/.pce files.

Now make something cool in HuC using the fantastic Squirrel sound engine by Aetherbyte!

cabbage
www.cabbage.cx
Twitter @HuCABBAGE
etc.