update XLC compiler defines
update XLC compiler defines

* CXX_DIALECT_PRE_11 uses -qlanglvl=extended
* CXX_DIALECT_11 uses -qlanglvl=extended0x

biddisco/CMake,ptoharia/CMake,biddisco/CMake,ptoharia/CMake,ptoharia/CMake,biddisco/CMake,biddisco/CMake,ptoharia/CMake