curs_getyx(3) on FreeBSD

The text e16a4ed9b594, as FreeBSD 2.1.7.1-RELEASE, FreeBSD 2.1.7-RELEASE, FreeBSD 2.1.5-RELEASE, FreeBSD 2.0.5-RELEASE shipped it.

get ncurses cursor and window coordinates

curs_getyx(3) on FreeBSD now