There is an updated pull request by DBLouis against master on the void-packages repository

https://github.com/DBLouis/void-packages master
https://github.com/void-linux/void-packages/pull/34800

LLVM 13
This adds LLVM 13 and updates from LLVM 12.

*Work-in-progress*

The following packages need to be updated or patched:

- `beignet`
- `ispc`
- `qtcreator`

Rebuilt packages:

- `juCi++`
- `kdevelop`
- `codelite`
- `mesa`
- `include-what-you-use`
- `ccls`
- `clazy`
- `bpftrace`
- `qt5`
- `rtags`
- `shiboken2`
- `gnome-builder`
- `bcc`

A patch file from https://github.com/void-linux/void-packages/pull/34800.patch is attached