I have attached a better patch (I have not tried python+tk).

The idea is to use `csound->widgetGlobals' as a switch
for the fltk opcodes. If it is not-NULL, `csoundModuleInit'
sets only dummy opcodes and `widget_init' is bypassed
because the `widget_init' function (widgets.cpp) contains

  if (csound->widgetGlobals == NULL) ...

For example, to disable fltk, it is enough

  csound->widgetGlobals = malloc(1);

and

  static int DummyExitGraph(CSOUND *csound)
  {
      IGN(csound);
      return 0;
  }

  static int dummy_widget_reset(CSOUND *csound, void *pp)
  {
      IGN(pp);
      free(csound->widgetGlobals);
      return OK;
  }

  csound->SetExitGraphCallback(csound, DummyExitGraph);
  csound->RegisterResetCallback(csound, NULL, dummy_widget_reset);

tito