* fhandler.h (fhandler_termios::line_edit): Add parameter to return

written bytes.
	* fhandler_termios.cc (fhandler_termios::tcinit): Fix formatting.
	(fhandler_termios::line_edit): Return bytes actually written.  Write
	in 32 byte chunks in non-canonical mode to reduce number of WriteFile
	calls.  Don't just eat unwritten bytes in case of an error condition.
	Especially, don't report them back to the caller as written.
	* fhandler_tty.cc (fhandler_pty_slave::read): Disable code reducing
	the number of bytes read from the pipe to vmin.  Add comment.
	(fhandler_pty_master::write): Convert ret to ssize_t type.  Just call
	line_edit once, not in a loop once for each byte.  Return bytes written
	as returned by line_edit.

winsup/cygwin/fhandler.h

@@ -1204,7 +1204,8 @@ class fhandler_termios: public fhandler_base
     need_fork_fixup (true);
   }
   HANDLE& get_output_handle () { return output_handle; }
-  line_edit_status line_edit (const char *rptr, int nread, termios&);
+  line_edit_status line_edit (const char *rptr, size_t nread, termios&,
+			      ssize_t *bytes_read = NULL);
   void set_output_handle (HANDLE h) { output_handle = h; }
   void tcinit (bool force);
   bool is_tty () const { return true; }