Without the change build fails on ncurses-6.5 (enables opaque WINDOW by
default) as:
aacurses.c: In function 'curses_getsize':
aacurses.c:74:20: error: invalid use of incomplete typedef 'WINDOW' {aka 'struct _win_st'}
74 | *width = stdscr->_maxx + 1;
| ^~