keyok - enable or disable a keycode
int keyok(int keycode, bool enable);
This is an extension to the curses library. It permits an application
to disable specific keycodes, rather than use the keypad function to
disable all keycodes. Keys that have been disabled can be reenabled.
The keycode must be greater than zero, else ERR is returned. If it
does not correspond to a defined key, then ERR is returned. If the
enable parameter is true, then the key must have been disabled, and
vice versa. Otherwise, the function returns OK.
These routines are specific to ncurses. They were not supported on
Version 7, BSD or System V implementations. It is recommended that any
code depending on them be conditioned using NCURSES_VERSION.