>getaddrinfo_a is available, but not widely adopted (*BSD and Linux), probably because you can't guarantee it'll be available on every computer/phone/modem. This is only an issue if you're targeting POSIX rather than modern operating systems.

To be precise, even on Linux getaddrinfo_a is not guaranteed to be present. It's a glibc extension. musl doesn't have it.

And MUSL's explicit policy of "do not implement essential features, just because the standards are falling behind" is a major reason why many programs choose to never support building against MUSL.