NixOS/nixpkgs — pull request #2769 by lethalman (2014-05-27 07:32:47+00:00)
Title: pkg-config: update to 0.28

See http://lethalhydra.noip.me/jobset/nixpkgs-pr/pkgconfig-0.28 .
I've updated the patch, it seems that most of changes have been included upstream. @vcunat @edolstra maybe it's possible to include this in the next mass rebuild?