#include "exim.h"
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
#include <idna.h>
#include <punycode.h>
string_is_utf8(const uschar * s)
{
uschar c;
-while ((c = *s++)) if (c & 0x80) return TRUE;
+if (s) while ((c = *s++)) if (c & 0x80) return TRUE;
return FALSE;
}