noping: Fix compatibility with ncurses 5.8.

noping: Fix compatibility with ncurses 5.8.

Hello,

My name is Gaetan and I maintain liboping in Arch Linux; our distro is
in the process of switching to ncurses-5.8, and I wanted to report that
I had to patch liboping to make noping work with the newer ncurses.

Specifically, if I update ncurses and run the old noping binary, then
nothing is displayed in the ncurses window (although the summary output
displayed on stdout at the end is correct). Same if I recompile noping
against the new ncurses library.

The reason seems to be that calling newwin() with ncols=0 does not
produce a full width window anymore. Anyway, the simple patch attached
fixed this issue for me.

Cheers.

Signed-off-by: Florian Forster <octo@verplant.org>