fixed a Windows compiler warning (Chris Poblete) fix for mod when dividend

* valid.c: fixed a Windows compiler warning (Chris Poblete)
* xpath.c: fix for mod when dividend is 0 (Chris Poblete)
Daniel
diff --git a/xpath.c b/xpath.c
index b716fa6..0dba1f0 100644
--- a/xpath.c
+++ b/xpath.c
@@ -4422,7 +4422,10 @@
     CAST_TO_NUMBER;
     CHECK_TYPE(XPATH_NUMBER);
     arg1 = (int) ctxt->value->floatval;
-    ctxt->value->floatval = arg1 % arg2;
+    if (arg2 == 0)
+	ctxt->value->floatval = xmlXPathNAN;
+    else
+	ctxt->value->floatval = arg1 % arg2;
 }
 
 /************************************************************************