Azure is a GUI generation library that uses XML to define GUIs dynamically. Azure frees developers from recompiling to make GUI changes and saves them from writing boring GUI code. You can read more about Azure on the About page. Azure uses Gtk+ and Xerces, the Apache Software Foundation's XML parsing library. There is also the begining of a tutorial.
Azure should run on any UNIX-like system, so if you don't have one... porting efforts are always welcome. Beyond that it lives on top of two independant libraries: