libresolv

resolv.h exposes facilities to resolve DNS records. See:

• Google Bionic
• GNU C Library (I admit that I am slightly confused why it is not mentioned in the GNU C Library Manual.)
• musl
• FreeBSD

I would like to understand whether there is a particular reason why the symbols in resolv.h are not covered by the libc crate. If there is no particular reason, I would like to start working on inclusion. My original motivation is to resolve DNS records (of type SRV, TXT) and realized that the Rust standard library does not support this. My next natural step was to check the libc crate.

Target Triples: *-unknown-linux-gnu, *-unknown-android, *-unknown-freebsd (* to be narrowed down by testing).

References:

• Zig seems to support it: https://github.com/ziglang/zig/issues/12628
• There's a resolv crate, which wraps libresolv-sys. It might benefit from this API.

Start by comparing the symbols and platform differences in resolv.h from Bionic, glibc, musl, and FreeBSD. Check the libc crate's existing platform bindings and test coverage for *-unknown-linux-gnu, *-unknown-android, and *-unknown-freebsd; done means determining supported target triples and covering the relevant libresolv APIs.