All cycle servers have DevToolSet installed and gcc versions 4.9.2 and 5.3.1 are available. Version 4.8.5 is the default gcc version. You can use scl to control which version you want to use (bash starts a new shell with all variables set).

devtoolset-3 - version 4.9.2
devtoolset-4 - version 5.3.1