Thread: pgsql: Prevent to_char(interval) from dumping core on month-related

Log Message:
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Prevent to_char(interval) from dumping core on month-related formats
when a zero-month interval is given.  Per discussion with Karel.
Also, some desultory const-labeling of constant tables.  More could be
done along that line.

Modified Files:
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    pgsql/src/backend/utils/adt:
        formatting.c (r1.85 -> r1.86)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/formatting.c.diff?r1=1.85&r2=1.86)