The GNUstep GUI library is a powerful library of graphical user interface
classes written completely in the Objective-C language; the classes are
based upon the OpenStep specification, and provide the user with a
traditional nextstep-like look and feel. The classes include graphical
objects such as windows, menus, buttons, text fields, popup lists, browsers,
scrollviews, splitviews, fonts, colors, images, events, pasteboards...
You need the corresponding backend library package (gnustep-back) to use