Historical behavior is to stop option parsing at the first non-option argument.
Since we have added more options, it seemed impractical to keep that behavior.
However people are using options in their abbr expansions ("abbr e emacs
-nw"). To support this, we ignore options. However, we only ignore them
if they are not valid "abbr" options. Let's ignore all options in the
expansion definition, which is a small price to pay to keep most existing
configurations working.
Fixes#9410
This does not fix other cases which used to work, like
abbr x -unknown
Those are hopefully not used by anyone, so I don't think we need to maintain
support for that.
9790907ca8