FAQ

   This requires wizardry so extreme that the authors have never tried
   it, though in principle it can be done.
   
    5.5) I have changed a source file. Why does the recompile not see the
    change?
    
   The Makefiles do not have the proper dependencies for include files.
   You have to do a make clean and then another make. If you are using
   GCC you can use the --enable-depend option of configure to have the
   compiler compute the dependencies automatically.