applied a patch from Gman for building docs applied a patch from Gary

* doc/*: applied a patch from Gman for building docs
* valid.c xmllint.c include/libxml/valid.h: applied a patch from
  Gary Pennington to provide an allocator for xmlValidCtxt
* xmlreader.c: applied patch from Jacek Konieczny fixing bug
  #113580 about data not being passed immediately.
Daniel

valid.c

@@ -680,6 +680,36 @@ xmlValidBuildContentModel(xmlValidCtxtPtr ctxt, xmlElementPtr elem) {
  *								*
  ****************************************************************/
 
+/**
+ * xmlNewValidCtxt:
+ *
+ * Allocate a validation context structure.
+ *
+ * Returns NULL if not, otherwise the new validation context structure
+ */
+xmlValidCtxtPtr
+xmlNewValidCtxt(void) {
+    xmlValidCtxtPtr ret;
+
+    if ((ret = xmlMalloc(sizeof (xmlValidCtxt))) == NULL)
+	return (NULL);
+
+    (void) memset(ret, 0, sizeof (xmlValidCtxt));
+
+    return (ret);
+}
+
+/**
+ * xmlFreeValidCtxt:
+ * @cur:  the validation context to free
+ *
+ * Free a validation context structure.
+ */
+void
+xmlFreeValidCtxt(xmlValidCtxtPtr cur) {
+    xmlFree(cur);
+}
+
 /**
  * xmlNewElementContent:
  * @name:  the subelement name or NULL