Also, mark systems as immutable so that at startup there is no slow
ASDF initialization and reloading of code.

Don't try to use the sound card when silent.

Nix recipe needs more work anyway for library dependencies,
at which point it can find the proper path to cl-launch.

Less jitter through pre-decompression of samples.
Use package-inferred-system from ASDF 3.1. Drop XCVB support.

Workaround: wait 5 seconds before exit (yuck).

Also, use samples from FreeSound.org, all converted to 44100 Hz to make mixalot happier.
Finally, improve the output and provide a #!/usr/bin/cl script.

Add a quick HOWTO manual in the asd file.