What is the purpose of the AraC gene in pGLO?
The AraC gene can activate GFP expression, because the GFP in the pGLO plasmid has the negative inducible pBAD promoter:
In the absence of arabinose an AraC protein dimer binds the promotor region, but does not activate transcription. When arabinose is present, the protein binds in a different way, which allows the downstearm gene (here GFP) to be produced.

According to this plasmid map I found the AraC and GFP genes are in different orientations (and facing 'away' from each other), so transcription of AraC wouldn't run over into GFP even without a terminator present.