Use the upstream OpenBSD implementations of these functions.
Also ensure we have symbols for htonl, htons, ntohl, and ntohs.
gtest doesn't like us using the macro versions in ASSERT_EQ.
Bug: 14840760
Change-Id: I68720e9aca14838df457d2bb27b999d5818ac2b5
This is part of the upstream sync (Net/Open/Free BSDs expose the
nameser.h in their public headers).
Change-Id: Ib063d4e50586748cc70201a8296cd90d2e48bbcf