% cat /etc/redhat-release Scientific Linux release 7.3 (Nitrogen)
The default compiler coming with SL6 was installed.
% gcc --version gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-11)
Other revisions are in /opt/gcc at BNL and this location is supported by the STAR login's 'setup' script. Note that an alternative to set another compiler location is supported via an environment variable named USE_GCC_DIR. See documentation Setting up your computing environment for more information.
The secondary compiler choice is gcc 4.8.2 (so we connect smoothly with the past 4.8.2/SL6.5 and 4.6.3/SL6.2 library releases) and we also have 4.4.7 so we can go backward as far as SL11).
The AFS fs sysname for those systems is a canonical x8664_sl7.
Since the transition begins at SL7.3, gcc 4.8.5, the new base for STAR software is sl73_gcc485 and sl73_x8664_gcc485 for the 32 and 64 bits versions respectively.
Possible support for variation of SL version / gcc version combinations (each greater than the base) would go through those directories. Possible supports of SL7.x x < 3 and/or gcc versions lower than 4.8.5 would have to be made toward the sl64_gcc482 and sl64_x8664_gcc482 paths instead (in those cases, please fix the AFS sysname to be the one indicated as used for SL6).