$NetBSD: patch-bc,v 1.3 2009/07/06 22:01:34 joerg Exp $

--- lasso/xml/tools.c.orig	2009-03-27 17:12:48.000000000 +0100
+++ lasso/xml/tools.c
@@ -1210,7 +1210,7 @@ is_base64(const char *message)
 	const char *c;
 
 	c = message;
-	while (*c != 0 && (isalnum(*c) || *c == '+' || *c == '/' || *c == '\n' || *c == '\r')) c++;
+	while (*c != 0 && (isalnum((unsigned char)*c) || *c == '+' || *c == '/' || *c == '\n' || *c == '\r')) c++;
 	while (*c == '=' || *c == '\n' || *c == '\r') c++; /* trailing = */
 
 	if (*c == 0)
