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

https://github.com/tranzystorek-io/void-packages llvm15
https://github.com/void-linux/void-packages/pull/40821

[WIP] LLVM 15
[ci skip]

TODO:

- [ ] Adjust patches marked as `.patch.skip`
- [x] Make libomp a shlib (change so file name and install a symlink)
- [x] Avoid creating triplet dirs under /usr/

TODO LLVM rdeps:

- [ ] clazy (breaking changes in clang API)
- [x] beignet (https://github.com/void-linux/void-packages/pull/41529)
- [ ] ispc (1.18.1 supports LLVM `<= 14`)
- [ ] ldc (1.30.0 supports LLVM `<= 14`)
- [ ] ghdl (2.0.0 supports LLVM `<= 14`)
- [x] qt
- [ ] qtcreator (breaking changes in clang-format API)
- [ ] shiboken2 (tests failing with llvm15)
- [x] bpftrace (https://github.com/void-linux/void-packages/pull/39002)
- [ ] libclc (tests fail with unresolved calls https://gist.githubusercontent.com/tranzystorek-io/a2aa8a0d8010af5299f7d1ff9f82c22b/raw/6d316d99d6079990b73ae77d274dd120b9560589/LastTest.log)
- [x] zig

A patch file from https://github.com/void-linux/void-packages/pull/40821.patch is attached