[libc-commits] [libc] [libc] Refactor getopt to use standard reset and internal test hook (PR #197644)

[Jeff Bailey via libc-commits]

kaladron wrote:

Heya Alexey!  This patch does two main things:

1) Adds the much more common way of resetting state to our getopt implementation
2) Exposes an internal way of redirecting the error messages to a stream instead of stderr.

This came up because @lntue had a PR two years ago #79319 that made our hermeteic testing work against the external interfaces and I wanted to resurrect that (https://github.com/kaladron/llvm-project/tree/public-testing).  I was going to have to expose set_getopt_state and wound up doing more general clean up pass on this file.

https://github.com/llvm/llvm-project/pull/197644