Can't find initializer_list lib when compiling with Green hills compiler

I am using Green Hills compiler version "2015.1.7" and it gives me this error

E:\Repos\somepath\json.hpp", line 40: fatal error #5: could not open source file "initializer_list" #include <initializer_list> // initializer_list ^

i made sure to enable --std=c++11 in my cmakelists but still same issue ... when i searched in greenhills folder for initializer_list i didn't find it so it makes sense but is my compiler corrupted and missing files or greenhills doesn't support c++ std libraries ?