gcc version change breaks our paths without saying anything

[nsjarvis]

We had a silent gcc update at CMU, I think our updates might be automatic, and buildscripts correspondingly decided to set our paths to this new version, however as I was unaware that we had the new version, I had not compiled the code with that version, and the paths went nowhere. The first symptom of this was 'which hd_root' returning 'Command not found'. It has taken me A WHOLE FRUSTRATED HOUR to find out wtf was wrong. It would be great if the gluex_env script could check that the paths exist before sourcing them.

Is there a way to send the gcc version to the environment script?