hpcrun: make sure it compiles with old gcc env
hpcrun: make sure it compiles with old gcc env

Somehow Theta doesn't like us using c++11

HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit