cmake HAVE_STDCXX11 examples

alibaba/AliSQL storage/tokudb/ft-index/cmake_modules/TokuSetupCompiler.cmake :198 

check_cxx_compiler_flag(-std=c++11 HAVE_STDCXX11)

percona/PerconaFT cmake_modules/TokuSetupCompiler.cmake :230 

check_cxx_compiler_flag(-std=c++11 HAVE_STDCXX11)

oscarlab/betrfs cmake_modules/TokuSetupCompiler.cmake :201 

check_cxx_compiler_flag(-std=c++11 HAVE_STDCXX11)