dev-python/py-rrdtool needs to be EAPI=2 to make use of USE depends but distutils.eclass is not ready for that. Please, make it EAPI=2 aware. Thank you.
Created attachment 179324 [details, diff] distutils.eclass-EAPI2.patch Suggested patch.
Guys, this change blocks me from fixing bug 247889 so I went ahead and committed fix. A fix is a bit different from proposed here, but it's arose from discussion of similar change for gnome2.eclass (take a look on bug 239123 for details). If you have any problems with this change come to me and I'll do my best to fix that.