The configure script does seem to have a problem. Upcoming a patch that fixes it and xaos can save screenshots. Reproducible: Always
Created attachment 185801 [details] Ebuild with patch
Created attachment 185804 [details, diff] Patch for png support
Please attach diffs when you did changes to an ebuild. That would be much more handy for our devs.
Created attachment 185831 [details] Diff of the ebuild.
fixed in 3.4-r1. thanks.