* fhandler.h (class fhandler_console): Add members `insert_mode'.

* fhandler_console.cc (fhandler_console::dup): Duplicate `insert_mode'.
        (fhandler_console::fhandler_console): Initialize `insert_mode'.
        fhandler_console::char_command): Add terminal capabilities
        "enter insert mode" = \E[4h and "exit insert mode" = \E[4l.
        Care for insert mode on terminal capability "repeat char" = \E[x;yb.
        (fhandler_console::write_normal): Care for insert mode before writing
        to the console.
        (array keytable): Add keymapping for modified cursor and control
        block keys (xterm like).

winsup/cygwin/fhandler.h

@@ -652,6 +652,7 @@ private:
   DWORD dwLastButtonState;
   int nModifiers;
 
+  BOOL insert_mode;
   BOOL use_mouse;
   BOOL raw_win32_keyboard_mode;