'initializer_list' file not found

context:

you@laptop:~$ clang --version
Debian clang version 3.5.0-10 (tags/RELEASE_350/final) (based on LLVM 3.5.0)

But whenever I try make on a script which needs c++11 support I get the following output: fatal error: 'initializer_list' file not found

I have tried adding -stdlib=libc++ to CXXFLAGS with no success.

How do I fix the 'initializer_list' error? I double checked doing find /usr/include -name initializer_list and this returned:

/usr/include/c++/4.9/initializer_list /usr/include/c++/5/initializer_list

EDIT: here's the Makefile: http://ift.tt/2flXP5N