$NetBSD: patch-ab,v 1.1 2007/01/14 10:30:56 joerg Exp $

--- Xtrans.c.orig	2007-01-14 11:28:47.000000000 +0100
+++ Xtrans.c
@@ -180,8 +180,8 @@ TRANS(SelectTransport) (char *protocol)
     protobuf[PROTOBUFSIZE-1] = '\0';
 
     for (i = 0; i < PROTOBUFSIZE && protobuf[i] != '\0'; i++)
-	if (isupper (protobuf[i]))
-	    protobuf[i] = tolower (protobuf[i]);
+	if (isupper ((unsigned char)protobuf[i]))
+	    protobuf[i] = tolower ((unsigned char)protobuf[i]);
 
     /* Look at all of the configured protocols */