Closed issue by Piraty on void-packages repository

https://github.com/void-linux/void-packages/issues/11240

Description:
At times it happens that a piece of packaged software has more that a single license or the users can choose between licenses.
As is, Void Linux uses `,` to enumerate multiple licenses in the `license=` field in package templates, but that's not accurate.
Since SPDX identifiers are enforced for +1y now whenever templates are changed or added, i propose Void  complies to ~the full~ the SPDX standard even more and enforces the use of [SPDX License Expressions](https://spdx.org/spdx-specification-21-web-version#h.jxpfx0ykyb60) (including `AND` and `OR`).

Full spec: https://spdx.org/spdx-specification-21-web-version