Silence compiler warning on mingw

src/backend/libpq/pqcomm.c

@@ -30,7 +30,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.194 2007/07/23 10:16:54 mha Exp $
+ *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.195 2007/07/24 11:16:36 mha Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -245,7 +245,6 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 	int			fd,
 				err;
 	int			maxconn;
-	int			one = 1;
 	int			ret;
 	char		portNumberStr[32];
 	const char *familyDesc;
@@ -256,6 +255,9 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
 	struct addrinfo hint;
 	int			listen_index = 0;
 	int			added = 0;
+#if !defined(WIN32) || defined(IPV6_V6ONLY)
+	int			one = 1;
+#endif
 
 	/* Initialize hint structure */
 	MemSet(&hint, 0, sizeof(hint));