gtk+ : Gimp ToolKit + ( https://www.gtk.org/ )
qscintilla : Qt port of Neil Hodgson's Scintilla C++ editor control ( https://www.riverbankcomputing.com/software/qscintilla/intro )
wxGTK : GTK version of wxWidgets, a cross-platform C++ GUI toolkit ( https://wxwidgets.org/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a stuff
For Paludis use this rsync : rsync://gentoo.zugaina.org/stuff-portage
If you have a problem : ycarus(-at-)zugaina.org