make localizing STDOUT work properly in the debugger for perl 5.8.8

Running under the perl debugger (perl 5.8.8), 'local *STDOUT = *$stdout;' doesn't localize STDOUT properly.  Later perl versions and using 'local *STDOUT = *$stdout' work.  Since CGI/Emulate/PSGI.pm localizes STDOUT in this way, running plackup app.psgi under the perl debugger doesn't work in 5.8.8.

Changing local *STDOUT = $stdout to local *STDOUT = *$stdout makes this work on 5.8.8 and doesn't stop it working in newer versions.

$ cat d.pl
use strict;
use warnings;

use IO::File;
print "hello\n";

{
        my $stdout = IO::File->new_tmpfile;
        local *STDOUT = $stdout;
        print "yay!\n";
}

print "bye\n";

$ perl d.pl
hello
bye
$ PERLDB_OPTS="NonStop=1" perl -d d.pl
hello
yay!
bye
$