ld: symbol(s) not found for architecture x86_64 - clang error

Question

Here's my sample code -

#include <iostream>
#include <fst/fst-decl.h>
#include <fst/fstlib.h>


using namespace std;
using namespace fst;

int main() {

    cout << "!!!Hello World!!! Yay!" << endl; // prints !!!Hello World!!!
    StdVectorFst fst;
    return 0;
}

And I'm compiling it using this command:

g++ -stdlib=libc++ -std=c++11 -v sampleFST.cpp;

I'm using Google's openFST toolkit.

And upon running the command above I get the following error:

ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

Can anyone tell me what's wrong? I've looked up this issue on google and the fix for this results in a type_traits error (it's like a vicious cycle).