version: convert to parse-options

version: convert to parse-options

The "git version" command didn't traditionally accept any
options, and in fact ignores any you give it. When we added
simple option parsing for "--build-options" in 6b9c38e14, we
didn't improve this; we just loop over the arguments and
pick out the one we recognize.

Instead, let's move to a real parsing loop, complain about
nonsense options, and recognize conventions like "-h".

Signed-off-by: Jeff King <redacted>
Signed-off-by: Junio C Hamano <redacted>