fix a few warning raised by gcc-4.1 and latests changes Daniel

* c14n.c encoding.c xmlschemas.c xpath.c xpointer.c: fix a few
  warning raised by gcc-4.1 and latests changes
Daniel
diff --git a/c14n.c b/c14n.c
index 33a5803..bb7c9ba 100644
--- a/c14n.c
+++ b/c14n.c
@@ -1139,6 +1139,7 @@
     /* 
      * Save ns_rendered stack position
      */
+    memset(&state, 0, sizeof(state));
     xmlC14NVisibleNsStackSave(ctx->ns_rendered, &state);
 
     if (visible) {