bin/ant has a special OS X section that sets $JIKESPATH to all of the jars in /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Classes. This should be $JAVA_HOME/../Classes. CurrentJDK is a soft link to the system-wide default JDK which isn't necessarily the same JDK found at $JAVA_HOME. I suggest changing: OSXHACK="/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Classes" to: OSXHACK="$JAVA_HOME/../Classes"
patch applied, thanks.