extended #version windowing options

extended #version windowing options

When makedefs generates dat/options for #version, enhance the
formatting of the 'supported windowing systems' section with more
thorough word fill and also emphasize the actual window system names
so that user can tell what value to give to OPTIONS=window_system:%s
when picking one of them.  Before and after

Supported windowing systems:
    traditional tty-based graphics,
    terminal-based graphics using curses libraries, and X11
    with a default of tty.

Supported windowing systems:
    "tty" (traditional text with optional line-drawing), "curses"
    (terminal-based graphics), and "X11", with a default of "tty".