pgsql: Add 'day' field to INTERVAL so 1 day interval can be

Log Message:
-----------
Add 'day' field to INTERVAL so 1 day interval can be distinguished from
24 hours. This is very helpful for daylight savings time:

    select '2005-05-03 00:00:00 EST'::timestamp with time zone + '24 hours';
          ?column?
    ----------------------
    2005-05-04 01:00:00-04

    select '2005-05-03 00:00:00 EST'::timestamp with time zone + '1 day';
          ?column?
    ----------------------
    2005-05-04 01:00:00-04

Michael Glaesemann

Modified Files:
--------------
    pgsql/doc/src/sgml:
        func.sgml (r1.267 -> r1.268)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.267&r2=1.268)
    pgsql/src/backend/commands:
        variable.c (r1.109 -> r1.110)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/variable.c.diff?r1=1.109&r2=1.110)
    pgsql/src/backend/utils/adt:
        date.c (r1.112 -> r1.113)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/date.c.diff?r1=1.112&r2=1.113)
        formatting.c (r1.90 -> r1.91)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/formatting.c.diff?r1=1.90&r2=1.91)
        nabstime.c (r1.135 -> r1.136)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/nabstime.c.diff?r1=1.135&r2=1.136)
        selfuncs.c (r1.184 -> r1.185)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/selfuncs.c.diff?r1=1.184&r2=1.185)
        timestamp.c (r1.133 -> r1.134)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/timestamp.c.diff?r1=1.133&r2=1.134)
    pgsql/src/include/catalog:
        pg_proc.h (r1.376 -> r1.377)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h.diff?r1=1.376&r2=1.377)
        pg_type.h (r1.163 -> r1.164)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_type.h.diff?r1=1.163&r2=1.164)
    pgsql/src/include/utils:
        timestamp.h (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/timestamp.h.diff?r1=1.46&r2=1.47)
    pgsql/src/interfaces/ecpg/pgtypeslib:
        interval.c (r1.23 -> r1.24)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/interval.c.diff?r1=1.23&r2=1.24)
    pgsql/src/test/regress/expected:
        interval.out (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/interval.out.diff?r1=1.11&r2=1.12)