>I've noticed that NetBSD defines the internal members of the __window
>(WINDOW) structure to be minus a leading underscore (like, at least,
>Sun does).  Was this intentional? If so, what it the workaround for
>those programs that access the internals of this structure?

The best fix I have found for NetBSD curses is ncurses.
This the latest version of ncurses (1.8.5)
It available by anonymous ftp as:
netcom.com:pub/zmbenhal/ncurses/1.8.5.tgz

It is easy to adjust the Makefile for NetBSD w/shared libraries.

Advantages include colored text, line graphics, and vi doesn't redraw
the whole screen when you scroll one line.