Here is the procedure for using the cutbuffer extension.

1. Copy tkCutBuffer.c from exmh/misc directory into tk source directory.
2. add tkCutBuffer.o to WIDGOBJS defintion in tk Makefile.
3. Modify tk.h:
1223a1224,1225
> EXTERN int            Tk_CutBufferCmd _ANSI_ARGS_((ClientData clientData,
>                           Tcl_Interp *interp, int argc, char **argv));

4. Modify tkWindow.c:
107a108
>     {"cutbuffer",     Tk_CutBufferCmd},

5. re-make wish, possibly after a 'make clean'.

