[libc-commits] [libc] [libc] Set default visibility to 'hidden' and make entrypoints default (PR #97123)

[Joseph Huber via libc-commits]

jhuber6 wrote:

Okay, I updated this to add a new `LLVM_LIBC_GLOBAL` macro which does the `__asm__` trick so we don't always need `extern "C"`. However, because we still need the duplicate `LIBC_NAMESPACE` version of the symbol, both of these will sometimes exist.

I added a `LIBC_CONF_VISIBILITY` config that defaults to `default`. So, the new behavior is that everything will be `hidden` unless it's an entrypoint, in which case it will be given  `LIBC_CONF_VISIBILITY`.

https://github.com/llvm/llvm-project/pull/97123