Make use of the DNS query hook in the netcontext

This will allow netd to run queries over TLS:
https://android-review.googlesource.com/#/c/391513/
https://android-review.googlesource.com/#/c/380593/

Bug: 34953048
Test: Device tests pass.  No issues during manual testing.
Change-Id: I8d613322307fc40cdba59b82599eda753697278f
diff --git a/libc/dns/include/resolv_private.h b/libc/dns/include/resolv_private.h
index 284270c..77b03bf 100644
--- a/libc/dns/include/resolv_private.h
+++ b/libc/dns/include/resolv_private.h
@@ -504,8 +504,8 @@
 __LIBC_HIDDEN__ int		res_getservers(res_state,
 				    union res_sockaddr_union *, int);
 
-__LIBC_HIDDEN__ void res_setnetid(res_state, unsigned);
-__LIBC_HIDDEN__ void res_setmark(res_state, unsigned);
+struct android_net_context; /* forward */
+__LIBC_HIDDEN__ void res_setnetcontext(res_state, const struct android_net_context *);
 
 // We use the OpenBSD __res_randomid...
 u_int __res_randomid(void);