[libc-commits] [libc] [libc] Add LIBC_NAMESPACE_HIDDEN_DECL macro (PR #97109)

[Joseph Huber via libc-commits]

jhuber6 wrote:

So, this is pretty much how we export our symbols https://godbolt.org/z/4bdoeq5oh. Since it's in a namespace, if we put the visibility on everything it will still apply to the C symbols. So we need specific attributes on the entrypoints. We could potentially `#define LIBC_NAMESPACE [[gnu::visibility("hidden")]] __llvm_libc_STR(LLVM_VER)` as a fallback, but we should pass `-fvisibility=hidden` regardless.

https://github.com/llvm/llvm-project/pull/97109