Enable IPv6 connections to the server, and add pg_hba.conf IPv6 entries

if the OS supports it.  Code will still compile on non-IPv6-aware
machines (feature added by Bruce).

Nigel Kukard

src/include/libpq/pqcomm.h

@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pqcomm.h,v 1.72 2002/12/06 04:37:05 momjian Exp $
+ * $Id: pqcomm.h,v 1.73 2003/01/06 03:18:27 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -47,6 +47,9 @@ typedef union SockAddr
 {
 	struct sockaddr sa;
 	struct sockaddr_in in;
+#ifdef HAVE_IPV6
+	struct sockaddr_in6 in6;
+#endif
 	struct sockaddr_un un;
 } SockAddr;