RFC: packaging LinuxSampler (non-standard license exception)

I intend to package the LinuxSampler stack (libgig, liblscp, linuxsampler, qsampler, gigedit) and want to confirm the licensing is acceptable before opening the PR. LinuxSampler is distributed as GPL-2.0 with an additional exception. Quoting the README

The LinuxSampler library (liblinuxsampler) and its applications are distributed under the terms of the GNU General Public License (see COPYING file), but with the EXCEPTION that they may NOT be used in COMMERCIAL software or hardware products without prior written authorization by the authors.

This clause has kept the package out of Debian, and Ubuntu rejected it even from multiverse since GPL-2.0 section 6 forbids further restrictions, making redistribution itself arguably questionable without upstream permission (https://bugs.launchpad.net/ubuntu/+source/linuxsampler/+bug/252330). Arch nonetheless ships it in extra (https://archlinux.org/packages/extra/x86_64/linuxsampler/).

Is this acceptable in void-packages, presumably as repository=nonfree? Upstream has historically granted written authorizations case by case, but that does not scale to distro binaries. I considered asking the LinuxSampler developers first, but acceptance here is what actually gates the packaging. If explicit redistribution permission for Void would settle it, I can request that on the linuxsampler-devel list before opening the PR.

The rest of the stack carries no exception, but qsampler and liblscp have no use without the engine, so the viability of the whole set hinges on this. WIP at https://github.com/Rutpiv/void-packages/tree/linuxsampler.

Start by reviewing the LinuxSampler README and COPYING information quoted in the issue, then inspect the WIP linuxsampler branch in Rutpiv/void-packages. Confirm whether the GPL-2.0 exception permits Void packaging and whether the full libgig, liblscp, linuxsampler, qsampler, and gigedit stack can be accepted before opening a package PR.