merged 2.2 branch

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@7748 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dynlib.h

@@ -94,6 +94,9 @@ public:
      */
     static void * GetSymbol(wxDllType dllHandle, const wxString &name);
 
+    // return the standard DLL extension (with leading dot) for this platform
+    static wxString GetDllExt();
+
 private:
     /// forbid construction of objects
     wxDllLoader();