[libc-commits] [libc] [libc][wait] hard code __W_CONTINUED for SYS_waitid fallback (PR #125929)

[Nick Desaulniers via libc-commits]

nickdesaulniers wrote:

> LGTM, but we should look into adding some macro to define this value as a followup. It looks like the same value is used in `WIFCONTINUED`

I _think_ end users are supposed to use `WIFCONTINUED` to check if what they got back from `wait4` was a "continued status." i.e. the whole point is to hide the actual value and force users to check that.  That said, that forces users to use a conditional chain, and can't do a switch statement.

https://github.com/llvm/llvm-project/pull/125929