mac os compiling error

I started to compile on mac OS (el Capitan), and everything was going well until i ran cmake --build build.
It got to about %50 done, then it threw this error:

/Users/user/raylib-lua-sol/vendor/raylib/src/external/glfw/src/nsgl_context.h:38:10: fatal error: 
      'stdatomic.h' file not found
#include <stdatomic.h>
                ^
1 error generated.

How can i fix this?