postmaster dead on startup from unportable SSL patch

Someone had the bright idea that the postmaster's -i switch could
be redefined as
    -i    same as it ever was
    -is    accept only SSL connections

Unfortunately, implementing that requires a getopt() that understands
the GNU double-colon extension ("i::").  HPUX's getopt, which claims
to be fully conformant to POSIX.2 and about six other standards,
doesn't grok it.  Net result: postmaster is quitting on startup with
a "usage" message for me.  Doubtless it will also fail on most other
non-GNU-libc platforms.

Unless we want to get into the business of supplying a substitute
optarg() library routine, we're going to have to pick a more portable
switch syntax for SSL.  (I might also point out that "-is" used to
have a quite different interpretation, ie "-i -s", which could trip
up someone somewhere.)

I can see two reasonable choices: (a) pick a currently-unused
switch letter that you specify *in addition to* -i, if you want
only secure connections; (b) pick a currently-unused switch letter
that you specify *instead of* -i, if you want only secure connections.

I'd lean towards (a) except that both of the obvious choices, -s and -S,
are already taken.  If we go with (b), -I is available and perhaps not
a totally off-the-wall choice, but I can't say I really like it.

Comments?  Ideas?  Is it time to give up on getopt and go to multiletter
switch names?  (Of course that would break a lot of people's startup
scripts... but we may someday be forced into it... maybe it's better
to bite the bullet now.)

            regards, tom lane