autoconf: check for res_nquery explicitly

Creates a test that checks explicitly for res_nquery, which can be a
macro in resolv.h. Defines RESOLV_LIBS that contains any libraries that
need to be linked against.

Notes from later fix:

Based on the 2013-09-30 version of wip-port.  On FreeBSD, one must
include netinet/in.h to get the definitions for stuff in resolv.h.
Also, resolv.h's functions are part of libc instead of libresolv.

Signed-off-by: Alan Somers <asomers@gmail.com>
Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
Merge pull request #823 from ceph/port/detect-libresolv

autoconf: check for res_nquery explicitly