Move XML util from os to base repository

Since the dynamic linker depends on the XML utils and we plan to replace
the ancient 'Arg_string' with XML, it is time to move the 'Xml_node' and
'Xml_generator' to base/include.

repos/base/include/util/print_lines.h

@@ -11,8 +11,8 @@
  * under the terms of the GNU General Public License version 2.
  */
 
-#ifndef _INCLUDE__OS__PRINT_LINES_H_
-#define _INCLUDE__OS__PRINT_LINES_H_
+#ifndef _INCLUDE__UTIL__PRINT_LINES_H_
+#define _INCLUDE__UTIL__PRINT_LINES_H_
 
 #include <util/string.h>
 
@@ -93,4 +93,4 @@ void Genode::print_lines(char const *string, size_t len, FUNC const &func)
 	}
 }
 
-#endif /* _INCLUDE__OS__PRINT_LINES_H_ */
+#endif /* _INCLUDE__UTIL__PRINT_LINES_H_ */

repos/base/include/util/xml_node.h

@@ -18,10 +18,8 @@
 #include <base/exception.h>
 
 namespace Genode {
-
 	class Xml_attribute;
 	class Xml_node;
-
 }