l10ntools: avoid -Werror=deprecated-copy (GCC trunk towards GCC 9)

...by explicitly defaulting the copy/move functions (and, where needed in turn,
also a default ctor) for classes that have a user-declared dtor that does
nothing other than an implicitly-defined one would do, but needs to be user-
declared because it is virtual and potentially serves as a key function to
emit the vtable, or is non-public, etc.

Change-Id: I4b3833ceb9da0a83be45c808f163dfad97f9c946
Reviewed-on: https://gerrit.libreoffice.org/58164
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

l10ntools/inc/xmlparse.hxx

@@ -82,6 +82,11 @@ protected:
 public:
     virtual XMLNodeType GetNodeType() const = 0;
     virtual ~XMLNode(){}
+
+    XMLNode(XMLNode const &) = default;
+    XMLNode(XMLNode &&) = default;
+    XMLNode & operator =(XMLNode const &) = default;
+    XMLNode & operator =(XMLNode &&) = default;
 };