`res_search` became a proper symbol only in glibc 2.34. Until that it
was re-defined in headers, hitting the (in-)famous
https://github.com/ziglang/zig/issues/9485
glibc 2.34+:
resolv/resolv.h:int res_search (const char *, int, int, unsigned char *, int)
Old glibc:
resolv/resolv.h:#define res_search __res_search
Also, remove the toplevel includes, as they should never be included in
the first place: the headers are included explicitly when needed.
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