[Fluxus] build issue on g4 tiger

[gabor papp]

> So; any ideas about next steps or tests would be welcome.
it's really strange. the problem is that the SConstruct file tries to 
detect the path of the racket binary by executing 'which racket', which 
does not seem to work on your system. we should figure out why this happens.

if worst comes to worst you can pass the racket path to scons using 
command line parameters like:
scons RacketPrefix=/Applications/Racket\ v5.1

best,
gabor