Seems an explicit destructor is needed

Otherwise it is unresolved in an optimising Clang build when linking libsc.

Change-Id: I5f4d3facfe79793607396b83722ebd65ad8bb2ba

include/svx/svdundo.hxx

@@ -274,6 +274,8 @@ public:
 
     virtual void Undo();
     virtual void Redo();
+
+    virtual ~SdrUndoRemoveObj();
 };
 
 /**

svx/source/svdraw/svdundo.cxx

@@ -836,6 +836,10 @@ void SdrUndoRemoveObj::Redo()
     ImpShowPageOfThisObject();
 }
 
+SdrUndoRemoveObj::~SdrUndoRemoveObj()
+{
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 void SdrUndoInsertObj::Undo()