[llvm] [cmake] Exposes LLVM version number in the runtimes. (PR #84641)

[Mark de Wever via llvm-commits]

mordante wrote:

> I wonder if this could help with #57263.

These CMake values were already available to `clang-tidy`. This made them available for the run-times.

https://github.com/llvm/llvm-project/pull/84641