[llvm] Initial changes for llvm shared library build using explicit visibility annotations (PR #96630)

[Tom Stellard via llvm-commits]

tstellar wrote:

> I thought it might be this: https://github.com/tstellar/template-visibility/blob/testing/templates.h#L37
> 
> That buildbot is using clang 14.

If this is indeed the problem, i would recommend just disabling the annotations for clang < 15. (i.e. have the macros expand to nothing).

https://github.com/llvm/llvm-project/pull/96630