pgsql: Add Win32: > o Disallow encodings like UTF8 which which

Log Message:
-----------
Add Win32:

o Disallow encodings like UTF8 which which PostgreSQL supports
but the operating system does not (already disallowed by
pginstaller)

Modified Files:
--------------
pgsql/doc:
TODO (r1.1422 -> r1.1423)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.1422&r2=1.1423)