Careful PL/Perl Release Not Required

Hackers,

With regard to this (very welcome) commit:

> commit 50d89d422f9c68a52a6964e5468e8eb4f90b1d95
> Author: Andrew Dunstan <andrew@dunslane.net>
> Date:   Sun Feb 6 17:29:26 2011 -0500
>
>     Force strings passed to and from plperl to be in UTF8 encoding.
>
>     String are converted to UTF8 on the way into perl and to the
>     database encoding on the way back. This avoids a number of
>     observed anomalies, and ensures Perl a consistent view of the
>     world.
>
>     Some minor code cleanups are also accomplished.
>
>     Alex Hunsaker, reviewed by Andy Colson.

I just want to emphasize that this needs to be highlighted as a compatibility change in the release notes. As an
example,I currently have this code in PGXN to process a TEXT param to a function: 
   my $dist_meta = JSON::XS->new->utf8->decode(shift);

After I upgrade to 9.0, I will have to change that to:
   my $dist_meta = JSON::XS->new->utf8(0)->decode(shift);

The upshot is that in those cases where the raw bytes are what's actually wanted, users will have to modify their
functionsto turn off the utf8 flag. 

This probably won't be that common, but Oleg, for example, will need to convert his fixed function from:

> CREATE OR REPLACE FUNCTION url_decode(Vkw varchar) RETURNS varchar  AS $$
>   use strict;
>   use URI::Escape;
>   utf8::decode($_[0]);
>   return uri_unescape($_[0]); $$ LANGUAGE plperlu;

To:

> CREATE OR REPLACE FUNCTION url_decode(Vkw varchar) RETURNS varchar  AS $$
>   use strict;
>   use URI::Escape;
>   return uri_unescape($_[0]); $$ LANGUAGE plperlu;

So this needs to be highlighted in the release notes: If a PL/Perl function is currently relying on a parameter passed
inbytes, it will need to be modified to deal with utf8 strings, instead. 

Best,

David