title: how to change std flag of clang in mac? current clang version 10.0.1 is using c++98 flag
body: <p>Though documentation of clang says version 10.0.1 uses c++11 but I am trying to compile c++ programs using clang compiler and clang compiler explicitly need -std=c++11 flag to compile with c++11 version.Otherwise it gives error in codes.</p>