> Why have any glibc?

Maybe they want dns resolution to work properly

Are you talking about the TCP fallback that musl has also had for 2 years? https://www.openwall.com/lists/musl/2023/05/02/1

In any event, that makes no sense. Pretend for a moment that glibc has working DNS and musl doesn't have working DNS (not true, but let's pretend). You don't build your compiler chain with working DNS support and then use it to build programs without working DNS.

Does a compiler need to resolve DNS?