The ArcObjects SDK for Cross-Platform C++ development includes multiple widget sets for developers to use.
See Also:
Choosing between Motif, QT, and GTK on Solaris or LinuxChoosing between Qt and GTK on Windows
Developing with make and GTK using the Solaris/Linux command prompt
Developing with make and Qt using the command prompt
Developing with make and Motif using the Solaris/Linux command prompt
Developing with GTK using Visual Studio 2008 and NMake
Developing with Qt using Visual Studio 2008 and NMake