Enable creation of .pdb files in Windows build

Change-Id: Ie3c2af8b2c574428a4f12e9f3093d85bb333863a
Reviewed-on: http://review.couchbase.org/40802
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>