parse-opt: fake short strings for callers to believe in.

parse-opt: fake short strings for callers to believe in.

If we begin to parse -abc and that the parser knew about -a and -b, it
will fake a -c switch for the caller to deal with.

Of course in the case of -acb (supposing -c is not taking an argument) the
caller will have to be especially clever to do the same thing. We could
think about exposing an API to do so if it's really needed, but oh well...

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>