PGRP_PIPE causes error message with some simple code

[Mike Frysinger]

a user reported this issue here:
http://bugs.gentoo.org/show_bug.cgi?id=92349

if you enable the PGRP_PIPE option, this simple example will fail:
$ ( exec 3>&1; : `echo>&3` )
bash: 3: Bad file descriptor

disabling the PGRP_PIPE option and everything works as it should ... verified 
that Debian works (they dont enable the PGRP_PIPE option) and that Fedora 
fails (they enable the PGRP_PIPE option)

the user also proposed a patch:
http://bugs.gentoo.org/attachment.cgi?id=61460

figure i should forward the issue to people who are familiar with bash 
internals :)
-mike