[clang] Add support for dynamic libraries in CLANG_BOLT (PR #127020)

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serge-sans-paille wrote:

> I like the idea here. I wonder if this could be generalized somehow in `add_llvm_library` so that it could be applied to arbitrary libraries. I had wanted to try to generalize this for executable in `add_llvm_executable`.
> 
> I'm fine taking this patch as-is without generalizing it, but I'm curious if you think this would work as a follow up change in the future.

Thanks Tom for your review. Unfortunately this would require providing an executable to link to, and a relevant profiling scenario to gather instrumentation profile. That's very specific to each library, I don't think I want to do that now :-)

https://github.com/llvm/llvm-project/pull/127020