curs_insch(3) on FreeBSD

The text e85e80da1ef2, as FreeBSD 2.1.7.1-RELEASE, FreeBSD 2.1.7-RELEASE, FreeBSD 2.1.5-RELEASE, FreeBSD 2.0.5-RELEASE shipped it.

insert a character before cursor in a ncurses window

curs_insch(3) on FreeBSD now