QML gui is designed to be a modern and flexible replacement of internal gui. It is based on Qt's Declarative UI framework, therefore it could be run on ant Qt platform, including mobile platforms with touchscreens etc
First of all - you have to install Qt 4.6 and a SNAPSHOT of a Declarative UI With snapshot mentioned above you have to use exactly Qt version 4.6.0, for other 4.6.x releases you have to manually checkout Declarative UI from git. Qt version 4.7 is unsupported yet.
When you have prepared your Qt environment, it's time to build Navit:
At the scripts output you should have the following lines:
Graphics types: yes (default) '''qt_qpainter: yes (default)''' GUI types: '''qml: yes (configure parameter)'''
both of them are required for gui qml