Cygwin: console: Fix cursor position restore after screen alternation.

- If screen is alternated on console, cursor position is not restored
  correctly in the case of xterm compatible mode is enabled. For example,
  the shell prompt is shown at incorrect position after using vim.
  This patch fixes this problem.

winsup/cygwin/fhandler_console.cc

@@ -308,6 +308,9 @@ void
 fhandler_console::set_cursor_maybe ()
 {
   con.fillin (get_output_handle ());
+  /* Nothing to do for xterm compatible mode. */
+  if (wincap.has_con_24bit_colors ())
+    return;
   if (con.dwLastCursorPosition.X != con.b.dwCursorPosition.X ||
       con.dwLastCursorPosition.Y != con.b.dwCursorPosition.Y)
     {