Diff options

Hey,

Working away at being able to pass options to diff, and have come into a
(small) problem. Because of the way apr_getopt works, we either need to
enumerate every option that could be passed to diff, or we need to set
our apr_getopt_t's err field to 0, and handle APR_BADCH. This implies that
APR will no longer handle invalid options for us.

My idea was to follow the second approach, adding an UNKNOWN_OPTIONS variable
to each subcommand's svn_cl__cmd_desc_t. Then after we have determined the
subcommand, we error out if that subcommand doesn't expect unknown options.

Does this sound reasonable?

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kevin Pilch-Bisson                    http://www.pilch-bisson.net
     "Historically speaking, the presences of wheels in Unix
     has never precluded their reinvention." - Larry Wall
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