Add WXDLLEXPORT to friend declaration for GCC 3.2.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@18211 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/sysopt.cpp

@@ -46,7 +46,7 @@
 // singleton class so it can't be done in the dtor)
 class wxSystemOptionsModule : public wxModule
 {
-    friend class wxSystemOptions;
+    friend class WXDLLEXPORT wxSystemOptions;
 public:
     virtual bool OnInit();
     virtual void OnExit();