Hi,
I think it might be a good idea to update the volumeicon PKGBUILD (https://gitea.artixlinux.org/packages/volumeicon/src/branch/master/PKGBUILD) to the latest upstream version, as other distributions have done, for instance:
Debian (https://packages.debian.org/search?keywords=volumeicon&searchon=names&suite=all§ion=all), Ubuntu (https://packages.ubuntu.com/search?keywords=volumeicon&searchon=names&suite=all§ion=all), Fedora (https://packages.fedoraproject.org/pkgs/volumeicon/volumeicon/) ...
Then drop the patch, it's no longer necessary! :)
The url softwarebakery.com (https://softwarebakery.com/maato/volumeicon.html) or nullwise.com (http://nullwise.com/volumeicon.html) no longer appear to be active, however.