Build doesn't fail if od not installed

[Harald Becker]

 Hi!
> NTL the main problem here is that the missing "od" is detected but the script
> is continuing only to fail otherwise.
True. That's the topic, I'm not complaining about if od is required or
not. Just that the build succeeded and didn't just abort at that point,
with a possible command not found message from make/shell. I don't
expect any error handling. Just abort and say failure ... and not
success ... resulting in confusion, when busybox fails with a
segmentation fault when just doing a xxx --help ... which let to hours
of searching for what has gone wrong :-(

--
Harald