Created attachment 317492 [details] failed patch output qt-webkit-4.8.1+glib-2.31.patch does not work since at least Jul 2 for qt-webkit-4.8.9999. I've already built qt-webkit-4.8.9999 successfully without the patch so I re-added it as user patch.
commit a0a53ec318c331402c4561e680bc19d9c4c147cb [x11-libs/qt-webkit:4] Stop applying obsolete patch (bug 425164). The build failure with glib >= 2.31 has been fixed upstream. Thanks to Andreas Sturmlechner for reporting.