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

[Thomas Fransham via llvm-commits]

fsfod wrote:

Thanks for catching that, it wasn't my intention for any targets to be non functional until all the required changes have gone in, after which i can change default symbol visibility set to hidden for elf targets.
Something i do wonder about is if loadable llvm and clang plugins work on mingw currently? some of my later changes to make them work for windows could also fix them for mingw if they don't currently work.




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