wxWindows is a Class Library for C++, which provides a GUI for more than one platform. The current version supports OpenLook (XView), Motif and Windows 3.1. WxWindows has originally been developed at the Artificial Intelligence Applications Institute at the University of Edinburgh.
This version has been compiled for the use with OpenLook but there is a MS-Windows version as well. The whole package can be found under /usr/lib/wxwin.