The new ant wrapper shell script automatically determines what the JAVA_HOME variable should be 
set to, but it should also export the variable so the entire ant build process can have access to it.  
For instance, I use ant to build my java files, create my native JNI headers using javah, and then to 
compile the native code by exec-ing a shell script which I populate from the ant buildl.xml.  Within 
this script I need to know where JAVA_HOME is so I can include the jni.h file in my C compilation 
path.  Previous to your new wrapper script, I had my own, which exported JAVA_HOME and all 
worked wonderfully.

I have made the following one line change to your script and would suggest something similar:

case "`uname`" in
  CYGWIN*) cygwin=true ;;
  Darwin*) darwin=true
           if [ -z "$JAVA_HOME" ] ; then
             JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Home
             export JAVA_HOME
           fi
           ;;
esac

Thanks for listening, and keep up the excellent work!  Ant is great!

Cheers,

Levi