Please update the Qt 4 dependencies for the following packages: media-sound/qjackctl media-sound/qtractor media-sound/sonic-visualiser media-sound/traverso See tracker bug #217161.
qjackctl and qsynth (which wasn't on the list are updated now).
all done now
traverso should be able to use QT4_OPTIONAL_BUILT_WITH_USE_CHECK="opengl" after a new eclass change. The error messages when opengl is enabled will be less versbose, however. https://bugs.gentoo.org/show_bug.cgi?id=217161#c7