Fix how to access clipboard content at program start.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11710 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

examples/clipboard.cxx

@@ -155,9 +155,7 @@ int main(int argc, char **argv)
   win->end();
   win->resizable(tabs);
   win->show(argc,argv);
-#if defined(__APPLE__) || defined(WIN32)
   clip_callback(1, tabs); // use clipboard content at start
-#endif
   Fl::add_clipboard_notify(clip_callback, tabs); // will update with new clipboard content immediately or at application activation
 
   Fl_Image::RGB_scaling(FL_RGB_SCALING_BILINEAR); // set bilinear image scaling method