Both =conky-1.6.1 and =conky-1.7.0_rc1 ebuilds have 'ipv6' USEflag. AFAICS this USEflag either disables portmon for ipv6, or provides some MPD-related var to make. The problem is that I can't find any reference of such option neither within 1.6.1 nor 1.70_rc1 sources. Moreover, after removing the flag (and thus always-enabling portmon) conky builds and runs fine. Thus, I assume 'ipv6' flag within these ebuilds is some kind of relict without real use and should be removed.
If you take a look at conky-1.7.1.1 which I recently added to the tree, you will recognize that there is no ipv6 use flag anymore. Instead of this I added a portmon use flag which is enabled by default. I did this because the old use flag enabled portmon if the ipv6 use flag was disabled which also was the default setting so now the behavior is the same as before (portmon also makes more sense as the configure switch is also called portmon + to me the whole ipv6 flag seemed a bit confusing). As you said grepping through the conky sources reveals nothing related to the MPD_NO_IPV6=noipv6" variable so I removed this part from the ebuild. I think this should explain everything thus I will close this bug. If there are issues popping up please reopen.
Well, I wasn't precise enough — the bug was meant to be reported against older versions of conky ebuilds, especially the stable one.
Well please consider this new version as the fix for this bug. I think this minor issue and will not backport the changes to the older versions.
Maybe you should document the 'ipv6' flag in metadata.xml then?
+ 14 Jul 2009; Pielmeier Daniel <billie@gentoo.org> metadata.xml: + Document the ipv6 use flag.
