added check for self-assignment to wxPrintData::operator=() (thanks HP aCC for a genuinely useful warning) and also changed it return type to the standard one instead of void

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56744 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/cmndata.h

@@ -228,7 +228,7 @@ public:
     wxString GetFilename() const { return m_filename; }
     void SetFilename( const wxString &filename ) { m_filename = filename; }
 
-    void operator=(const wxPrintData& data);
+    wxPrintData& operator=(const wxPrintData& data);
 
     char* GetPrivData() const { return m_privData; }
     int GetPrivDataLen() const { return m_privDataLen; }