linux-kcc, linux-icc, linux-cxx. building QT

When I ran ./configure on the QT source tree, it said Build type: linux-g++ Platform notes: - Also available for Linux: linux-kcc linux-icc linux-cxx I've seen mention of kcc before, but never learned much about it. The other two options are new to me. What do these mean? How can I find documentation on them? The last time I looked, the documentation on kcc was something on the order of 'It's new. It's good. RTFS.' STH