Suppress platform-dependent unused-variable warning.

The local variable "sock" can be unused depending on compilation flags.
But there seems no particular need for it, since the kernel calls can
just as easily say port->sock instead.

src/backend/libpq/auth.c

@@ -1785,7 +1785,6 @@ ident_inet_done:
 static int
 auth_peer(hbaPort *port)
 {
-	int			sock = port->sock;
 	char		ident_user[IDENT_USERNAME_MAX + 1];
 
 #if defined(HAVE_GETPEEREID)
@@ -1795,7 +1794,7 @@ auth_peer(hbaPort *port)
 	struct passwd *pass;
 
 	errno = 0;
-	if (getpeereid(sock, &uid, &gid) != 0)
+	if (getpeereid(port->sock, &uid, &gid) != 0)
 	{
 		/* We didn't get a valid credentials struct. */
 		ereport(LOG,
@@ -1823,7 +1822,7 @@ auth_peer(hbaPort *port)
 	struct passwd *pass;
 
 	errno = 0;
-	if (getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) != 0 ||
+	if (getsockopt(port->sock, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) != 0 ||
 		so_len != sizeof(peercred))
 	{
 		/* We didn't get a valid credentials struct. */
@@ -1852,7 +1851,7 @@ auth_peer(hbaPort *port)
 	ucred_t    *ucred;
 
 	ucred = NULL;				/* must be initialized to NULL */
-	if (getpeerucred(sock, &ucred) == -1)
+	if (getpeerucred(port->sock, &ucred) == -1)
 	{
 		ereport(LOG,
 				(errcode_for_socket_access(),
@@ -1925,7 +1924,7 @@ auth_peer(hbaPort *port)
 	iov.iov_base = &buf;
 	iov.iov_len = 1;
 
-	if (recvmsg(sock, &msg, 0) < 0 ||
+	if (recvmsg(port->sock, &msg, 0) < 0 ||
 		cmsg->cmsg_len < sizeof(cmsgmem) ||
 		cmsg->cmsg_type != SCM_CREDS)
 	{