Stop using the private bionic headers

Note that only netd/server/ should link with libnetd_resolv. The client
portion and tests only need access to resolv/resolv_netid.h, and mostly
just to get the value of NETID_UNSET. We should consider moving this
somewhere else, perhaps system/netid/client.

We should also consider cleanly separating the public libnetd_resolv
interface and exporting them via a separate include path, following the
same pattern of libnetdutils and other libs.

Test: m netd netd_integration_test netd_unit_test netd_benchmark
Change-Id: I3a76cba254a9b05cb7c8e2d164540f9c0bb60ea9
7 files changed