Update the flags for C++11
Update the flags for C++11

chemfiles/chemfiles,lscalfi/chemfiles,lscalfi/chemfiles,lscalfi/chemfiles,chemfiles/chemfiles,Luthaf/Chemharp,chemfiles/chemfiles,chemfiles/chemfiles,lscalfi/chemfiles,Luthaf/Chemharp,Luthaf/Chemharp