pgsql: I made the patch that implements regexp_replace again.

Log Message:
-----------
I made the patch that implements regexp_replace again.
The specification of this function is as follows.

regexp_replace(source text, pattern text, replacement text, [flags
text])
returns text

Replace string that matches to regular expression in source text to
replacement text.

 - pattern is regular expression pattern.
 - replacement is replace string that can use '\1'-'\9', and '\&'.
    '\1'-'\9': back reference to the n'th subexpression.
    '\&'     : entire matched string.
 - flags can use the following values:
    g: global (replace all)
    i: ignore case
    When the flags is not specified, case sensitive, replace the first
    instance only.

Atsushi Ogawa

Modified Files:
--------------
    pgsql/doc/src/sgml:
        func.sgml (r1.263 -> r1.264)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.263&r2=1.264)
    pgsql/src/backend/regex:
        regexec.c (r1.24 -> r1.25)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/regex/regexec.c.diff?r1=1.24&r2=1.25)
    pgsql/src/backend/utils/adt:
        regexp.c (r1.56 -> r1.57)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/regexp.c.diff?r1=1.56&r2=1.57)
        varlena.c (r1.126 -> r1.127)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/varlena.c.diff?r1=1.126&r2=1.127)
    pgsql/src/include/catalog:
        catversion.h (r1.286 -> r1.287)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.286&r2=1.287)
        pg_proc.h (r1.374 -> r1.375)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h.diff?r1=1.374&r2=1.375)
    pgsql/src/include/regex:
        regex.h (r1.26 -> r1.27)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/regex/regex.h.diff?r1=1.26&r2=1.27)
    pgsql/src/include/utils:
        builtins.h (r1.259 -> r1.260)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/builtins.h.diff?r1=1.259&r2=1.260)
    pgsql/src/test/regress/expected:
        strings.out (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/strings.out.diff?r1=1.25&r2=1.26)
    pgsql/src/test/regress/sql:
        strings.sql (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/strings.sql.diff?r1=1.16&r2=1.17)