ICS and the latest GB update both fail to build using openJDK. Interestingly openJDK *did* build AOSP for quite a while. I know this because a number of co-workers where using openJDK without knowing it and I got to help debug their troubles after an update to AOSP happened.
FWIW I think it craps out in either an SDK or test project. (I don't recall which one was trouble maker)
I recomend folks to get the java from oracle web site and set the shell search path such that the javac used in the build is the one from the oracle JDK install directory and recommend NOT using any distro installed java for building AOSP.