* Note that this function doesn't protect whitespace and line endings
* from being processed according to the XML rules for normalization
* of line endings and attribute values.
+ *
+ * Note also that if given a string containing them, this function
+ * will produce character references in the range of  ..
+ *  for all control sequences except for tabstop, newline
+ * and carriage return. The character references in this range are
+ * not valid XML 1.0, but they are valid XML 1.1 and will be accepted
+ * by the GMarkup parser.
*
* Return value: a newly allocated string with the escaped text
**/