On Solaris, we should only force use of our own getopt(); it's okay to use

On Solaris, we should only force use of our own getopt(); it's okay to use
the system's getopt_long().  The previous coding was the result of a sloppy
discussion that failed to draw this distinction.  The result was that PG
programs don't handle options as users of that platform expect.  Per
gripe from Chuck McDevitt.

Although this is a pre-existing bug, I'm not backpatching since I think we
could do with a bit of beta testing before concluding this is really OK.