Too long lines in the echo area of the stand-alone Info reader

[Eli Zaretskii]

While working on the MinGW port of Info, I noticed an annoying
problem: the welcome message displayed in the echo area when the
reader starts up causes the entire display to scroll up one line,
which messes up the display until you scroll the main window once or
twice.

The current version string, "5.2dev", is just long enough to cause the
welcome message overflow the 80-column line width, so the code appends
the continuation backslash in the last column.  But at least on the
Windows console, doing so causes the cursor move into the beginning of
the next line, and since this is the last line of the screen, the
entire display is then scrolled up.

Looking through the code in display_update_window_1, I don't see any
attempt to handle this situation.  Does the code assume that writing a
character at the last column of the last display line doesn't cause
such a scroll?  If so, is that a portable assumption, even if only
Posix TTYs are considered?  ISTR that in the Less program there is a
more elaborate handling of at least 3 different behaviors in this
situation, perhaps Info should do something similar as well?

(I worked around this by forcing the Windows console not to wrap at
end of line, but I'm not sure there's a way to do that on every
platform and terminal we'd like to support.)

Or maybe I missed something?

Thanks.