libc on macOS does not provide at_quick_exit or quick_exit. This allows modules to build on macOS and defer any errors to usage site of these symbols. Fixes: https://github.com/llvm/llvm-project/issues/77559
libc on macOS does not provide at_quick_exit or quick_exit. This allows modules to build on macOS and defer any errors to usage site of these symbols. Fixes: https://github.com/llvm/llvm-project/issues/77559