qt Build Qt using the C++11 standard Add support for exceptions - like catching them inside the event loop (recommended by Nokia) Enable dev-libs/glib eventloop support Enable qmake optimization Install Qt declarative private headers required by Qt-creator QmlDesigner and QmlInspector plugins" Build a window system agnostic implementation of Qt Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.