* fhandler.h (fhandler_termios::echo_erase): Declare new method.

* fhandler_termios.cc (fhandler_termios::echo_erase): New method for echoing
erase characters.
(fhandler_termios::line_edit): Check the echo flag before echoing control
characters (from Kazuhiro Fujieda <fujieda@jaist.ac.jp>).

winsup/cygwin/fhandler.h

@@ -600,6 +600,7 @@ public:
   virtual void __release_output_mutex (const char *fn, int ln) {}
   void fixup_after_fork (HANDLE);
   void fixup_after_exec (HANDLE parent) { fixup_after_fork (parent); }
+  void echo_erase (int force = 0);
 };
 
 enum ansi_intensity