that when the options section is listed as "None", utility shall
recognize "--" as a first argument to be discarded.
This implementation is largely based on OpenBSD implementation but
we do slightly differently:
a) We skip argv[0] as the first step;
b) We test whether the next argument is "--" and ignore it.
With this change one will get:
%printf
usage: printf format [arguments ...]
%printf -v
-v%printf -- -v
-v%
%printf --
usage: printf format [arguments ...]
Which matches the behavior observed on a Debian system but different
from the Illumos change.
02a4a3f56c